Seven transmembrane receptors—A brief personal retrospective

Receptors have fascinated biologists for more than a century and they have fascinated me for the entirety of my own research career. The seven transmembrane receptors, also known as G protein coupled receptors, represent the largest of the several families of plasma membrane receptors, comprising more than a thousand genes and regulating virtually all known physiological processes in mammals. Moreover, they represent one of the commonest targets of currently used drugs. I have spent the entirety of my research career working on these receptors. Here I set down some personal reflections on the evolution of the field during the past 35 years, hanging the thread of the story on some of the work from my own laboratory.     

A career at the interface of cell and developmental biology: a view from the crest

Just as neural crest cells migrate great distances through the embryo, my journey has taken me from a childhood in a distant land to a career as a biologist. My mentoring relationships have shaped not only the careers of my trainees, but also the trajectory of my own science. One of the most satisfying aspects of mentoring comes from helping to empower the next generation of scientists to do more tomorrow than is possible today. This, together with a passion for discovery and learning new things, motivates me and makes science such a rewarding career.First, let me say how honored I am to receive the Women in Cell Biology Senior Award. I am particularly thankful to my former postdoctoral fellows and students. I have learned as much, or more, from them as they have from me and take great pride and vicarious pleasure from their successes. My goal as a mentor has been to impart an enthusiasm for science and for the satisfaction it can bring at both a professional and personal level. It is the pleasure of discovery and the bonds of collegiality that make being a scientist not only a worthwhile and interesting but also a very fulfilling career.When looking back upon my life as a biologist, many of the “choices” made along my career path were more of a random walk than a premeditated trajectory. Perhaps the most important and constant influences come from my family background, wonderful friends and colleagues, and an inherent interest in the natural world. For me, these were mixed with a good deal of luck and the generous mentorship of valued colleagues.     

A Developmental Journey and Lessons Learned Along the Way

A career in science is a journey of wonder and discovery. To succeed in science requires curiosity, perseverance, a good dose of luck, and wise guidance from those who have taken the journey ahead of you. We also need to use our science skills to contribute to public debate on complex issues of the day.Being honored by the 2009 American Society for Cell Biology Women in Cell Biology (WICB) Senior Award has provided me with an opportunity to look back and examine the importance of mentorship and role models, both female and male, in my career. I am fundamentally a basic biologist, driven by my curiosity about how the world works. The question that has fascinated me for over 30 years is one that we can all relate to: How is it that complex, rational organisms such as ourselves can arise from a single cell, the size of a speck of dust?Over the years my lab colleagues and I have explored many aspects of that question, using mice as our model system, and we''ve discovered more and more about the hierarchy of cell decisions that begins when sperm hits egg. Along the way we have contributed to the development of techniques for manipulating the mouse genome, helped identify key signaling pathways that control blood vessel development, and isolated novel stem cells from the mouse blastocyst. But I always return to the fundamental questions of lineage development in the early embryo, attacking the problem with new tools as they become available.     

Being at the right place at the right time

I am tremendously honored to receive the 2012 Women in Cell Biology Junior Award. In this essay, I recount my career path over the past 15 years. Although many details are specific to my own experiences, I hope that some generalizations can be made to encourage more women to pursue independent scientific careers. Mine is a story of choosing a captivating question, making the most of your opportunities, and finding a balance with life outside the lab.It is a great honor to have been awarded the 2012 Women in Cell Biology Junior Award from the ASCB. Looking back at the 15 years I have spent doing research in cell biology, my overwhelming feeling is that it has been and still is a lot of fun. I am extremely fortunate to have a job that I truly enjoy and that gives me complete intellectual freedom. My lab choices over the years were motivated by scientific curiosity and enthusiasm for new environments and topics, rather than by career building. It is thus truly amazing to be rewarded for (rather a lot of) work enjoyed.     

Support for a career in science

I am so very honored to receive the Women in Cell Biology Sandra K. Masur Senior Leadership Award from the American Society for Cell Biology (ASCB), particularly because many of the previous awardees have served as mentors and sources of inspiration throughout my own career. I also thank the ASCB for always striving to be maximally inclusive, in terms of both the scientists it supports and its broad vision of what constitutes cell biology. As a graduate student I gave one of my first talks at an ASCB meeting, and I am proud to have been an ASCB member for almost 30 years. In this essay, I describe my own career to illustrate the support that I believe is needed to achieve a career in science.

S. L. Wolin     

Crafting a career in molecular animation

When I first set out on a path to becoming a cell biologist, I would have never imagined that it would lead to a career in molecular animation. I had always thought I would follow a more traditional route. What happened? In this essay, I will describe the experiences that led to my decision to forge a career as an academic molecular animator, and how my work has evolved over the years. I will also provide some resources and advice for those who may be considering following a similar route.     

The Chemical Synthesis of DNA/RNA: Our Gift to Science

It is a great privilege to contribute to the Reflections essays. In my particular case, this essay has allowed me to weave some of my major scientific contributions into a tapestry held together by what I have learned from three colleagues (Robert Letsinger, Gobind Khorana, and George Rathmann) who molded my career at every important junction. To these individuals, I remain eternally grateful, as they always led by example and showed many of us how to break new ground in both science and biotechnology. Relative to my scientific career, I have focused primarily on two related areas. The first is methodologies we developed for chemically synthesizing DNA and RNA. Synthetic DNA and RNA continue to be an essential research tool for biologists, biochemists, and molecular biologists. The second is developing new approaches for solving important biological problems using synthetic DNA, RNA, and their analogs.     

Astrocytes Provide Metabolic Support for Neuronal Synaptic Function in Response to Extracellular K<Superscript>+</Superscript>

It is an honour to have this opportunity write an article in recognition of the immense contributions of Bruce Ransom to the field of glial research. For me (BAM) personally there are many highlights both as a colleague and a friend that come to mind when I reflect on the many years that I have known Bruce. My own entry into the glial field was inspired by the early work by Ransom and his lab showing the sensitivity of astrocytes to neuronal activity. During my PhD and postdoctoral research I read these early papers and was inspired to ask the question when I first set up my independent lab in 1983: what if astrocytes also express some of the multitude of ion channels or transmitter receptors that were beginning to be described in neurons? Could they modify neuronal excitability during seizures or behaviour? As it turned out this was not only true but glial-neuronal interactions continues to be a growing and exciting field that I am still working in. I first met Bruce at the 1984 Society for Neuroscience meeting in Anaheim at my poster describing voltage gated calcium channels in astrocytes in cell culture. That was the start of a great friendship and years of discussions and collaborations. This review describes recent work from my lab led by Hyun Beom Choi that followed and was inspired by the groundbreaking studies by Bruce on electrophysiological and pH recordings from astrocytes and on glycogen mobilization in astrocytes to protect white matter axons.     

A career pathway in protein folding: from model peptides to postreductionist protein science

This review discusses the inherent challenge of linking "reductionist" approaches to decipher the information encoded in protein sequences with burgeoning efforts to explore protein folding in native environments-"postreductionist" approaches. Because the invitation to write this article came as a result of my selection to receive the 2010 Dorothy Hodgkin Award of the Protein Society, I use examples from my own work to illustrate the evolution from the reductionist to the postreductionist perspective. I am incredibly honored to receive the Hodgkin Award, but I want to emphasize that it is the combined effort, creativity, and talent of many students, postdoctoral fellows, and collaborators over several years that has led to any accomplishments on which this selection is based. Moreover, I do not claim to have unique insight into the topics discussed here; but this writing opportunity allows me to illustrate some threads in the evolution of protein folding research with my own experiences and to point out to those embarking on careers how the twists and turns in anyone's scientific path are influenced and enriched by the scientific context of our research. The path my own career has taken thus far has been shaped by the timing of discoveries in the field of protein science; together with our contemporaries, we become part of a knowledge evolution. In my own case, this has been an epoch of great discovery in protein folding and I feel very fortunate to have participated in it.     

Hongyuan Yang: Tracking lipids,one droplet at a time

Hongyuan Yang investigates lipid trafficking and lipid droplet biogenesis.

Hongyuan Yang grew up in a small city east of Beijing, China. From his childhood, Hongyuan recalls that “food was not abundant, so I was hungry at times, but education was free and good.” Driven by his curiosity for science, after completing his undergraduate studies at Peking University Health Science Center, China, he enrolled at Columbia University, NY, for his doctoral training. Under the guidance of his advisor, Dr. Stephen Sturley, Hongyuan studied lipids in budding yeast. The laboratory’s research department fostered a strong interest in lipids and atherosclerosis, and after earning his PhD, Hongyuan obtained a faculty position at the National University of Singapore (NUS) in 1999. In 2007, he moved to the University of New South Wales (UNSW) in Sydney, Australia, to continue his scientific journey exploring lipids. We contacted Hongyuan to learn more about his career and interests.Hongyuan Robert Yang. Photo courtesy of UNSW.What interested you about lipids?My five-year doctoral study focused entirely on the enzymes Sterol O-Acyltransferases (SOAT, also known as ACAT, Acyl-CoA Cholesterol Acyltransferases), which catalyze the formation of sterol esters from sterols/cholesterol and fatty acyl CoAs (1). SOATs, integral membrane proteins of the ER, are potential therapeutic targets for heart disease and Alzheimer’s disease. Since then, I have been fascinated by two things related to SOAT: first, what happens upstream of SOAT, i.e., how exogenous cholesterol reaches SOAT/ER; and second, what happens downstream of SOAT, i.e., how its product—cholesterol esters—is stored in cells in the form of lipid droplets (LDs).These are fundamental questions in cell biology. While reading on how cholesterol arrives at the ER for esterification by SOAT/ACAT in the late 1990s, I realized that the trafficking of most lipids was poorly characterized with little molecular insight. Significant progress has been made in the last 20 years, but the lack of tools that track the movement of lipids has hampered our understanding of the selectivity, efficacy, and kinetics of lipid trafficking. Few cell biologists cared about LDs ∼20 years ago, even though LDs are prominent cellular structures in many disease conditions. Each LD comprises a hydrophobic core of storage lipids (triglycerides and sterol esters) wrapped by a monolayer of phospholipids. Largely considered inert lipid granules, LDs originate from the ER and are relatively simple cellular structures as compared with other organelles (see image). Now, we know that LDs are not that simple: their biogenesis is tightly regulated, they actively interact with other organelles, and they regulate many aspects of cellular function as well as disease progression. Astonishingly, we still have little understanding of how LDs originate from the ER. I am very much intrigued by the complexity of these two seemingly simple cellular processes, i.e., lipid trafficking and LD biogenesis.What are some of the scientific questions currently of interest in your laboratory?We are currently focusing on how LDs originate from the ER. The first significant paper from my own laboratory was the discovery of seipin as a key regulator of LD formation (2). Results from many groups have demonstrated that seipin can organize the formation of LDs; however, the exact molecular function of seipin remains mysterious. Our data suggest that seipin may directly impact the level and/or distribution of lipids such as phosphatidic acid near sites of LD biogenesis, and the effect of seipin deficiency on LD formation is secondary to changes in local lipids. We are now working hard to test this hypothesis. Moreover, data from my laboratory and others indicated that nonbilayer lipids may have a greater impact on the biogenesis of LDs than that of other ER-derived structures, such as COPII vesicles. This may result from the monolayer nature of the LD surface. We hope to dissect the dynamic changes of lipids at ER domains where LDs are born. More broadly, the ER is a fascinating organelle to me. The simple division of ER into sheets and tubules does not reflect the dynamic nature of this organelle. Dissecting the composition and organization of lipids and proteins of the ER would help answer key questions relating to LD biogenesis, and it is therefore one of our future directions.Another major focus is to understand how cholesterol and phosphatidylserine are moved between organelles. We have been working on how low-density lipoprotein (LDL)–derived cholesterol (LDL-C) reaches the ER for two decades. The release of LDL-C from lysosomes requires the Niemann Pick C1&2 proteins, whose malfunction causes lysosomal cholesterol accumulation and a lethal genetic disorder affecting young children. The Ara Parseghian Medical Research Foundation has led the way in supporting research into cholesterol trafficking, and I take this opportunity to thank their generous support. Once released from lysosomes, LDL-C is believed to reach the plasma membrane first and then the ER. We identified ORP2 as a possible carrier of LDL-C to the plasma membrane using a PI(4,5)P₂ gradient (3). There must be other carriers and/or pathways because ORP2 deficiency only causes a minor accumulation of cholesterol in lysosomes. Another interesting question is what prevents LDL-C from reaching the ER directly from lysosomes, given the close contact between lysosomes and the ER. We reported that ORP5 may bring LDL-C directly to the ER (4). However, it was later found that ORP5 binds and transfers phosphatidylserine, not cholesterol. Thus, our observed link between ORP5 and cholesterol is through some indirect yet unknown mechanism. We have been perplexed by these observations for many years, but a recent study demonstrated that phosphatidylserine is required for the trafficking of LDL-C, establishing a close link between cholesterol and phosphatidylserine (5). We are now trying to understand how the trafficking and distribution of cholesterol, phosphatidylserine, and PI(4,5)P₂ are interconnected. For a long time, I felt that it was impossible to figure out the molecular details governing the cellular trafficking of lipids due to redundant pathways and a lack of tools to track lipids. Recent progress in this field has given me hope.Lipid droplets in a HeLa cell are shown in red (BODIPY), with their surface in green. DAPI (blue) labels DNA. Image courtesy of Hongyuan Yang.What kind of approach do you bring to your work?Besides honesty and open-mindedness, we emphasize rigor and comprehensiveness. We often make our initial discoveries in cell-based screens. This approach has many advantages, but it also gives rise to artifacts and cell-line specific observations. We aim to complement our initial findings with biochemical and structural analyses in vitro as well as animal studies in vivo. To further establish the reproducibility of our data, I often ask my close friends and collaborators to independently repeat the key findings of a study before submission. It generally takes a long time for us to complete a study, but I believe the effort will pay off in the long run.What did you learn during your training that helped prepare you for being a group leader? What were you unprepared for?During my PhD at Columbia, I was most impressed with the general attitude of my mentors toward research. No matter how much they have achieved, they take every new experiment and every poster presentation seriously.As I did not have postdoctoral training, I was somewhat unprepared at the beginning of my independent career. One difficult challenge was knowing when to finish a paper and project. We often kept working and working. I have now gotten a lot better.You’ve done research on three continents throughout your career. Can you tell us about some of these transitions?During the last year of my doctoral studies at Columbia, I was offered a lecturer position by the Department of Biochemistry at NUS. It was a very hard decision to leave the United States, but I was excited by the prospect of starting my own laboratory at a top institution. Life at NUS was very good overall, despite some struggles. I had to make ∼700 slides for teaching during the first year and my start-up fund was 10,000 Singapore dollars (~6,000 USD). But the graduate students were fully supported by the university, and most of them are hard working and talented. The crucial screen that led to the discovery of seipin as a key regulator of LD formation was performed at NUS (2). I enjoyed my time at NUS, where I was promoted and tenured. However, my family and I could not get used to the heat and humidity. We looked for a place with better climate, and it happened that my current employer, UNSW, had an opening in 2006. Moving continents with two kids was very disruptive, and I had zero publications in 2007. Our work on seipin was delayed and almost got scooped. I was also very worried about funding in Australia since I hardly knew anyone and the funding system. It turned out that the Australian community was very supportive of our research from day one. I have also been very fortunate to receive generous support from the Ara Parseghian Medical Research Foundation, based in the United States, after my move to Sydney.Hongyuan’s “metabolism team” after a basketball game. Photo courtesy of Hongyuan Yang.What has been the biggest accomplishment in your career so far?While I am mostly recognized for discovering seipin’s role in lipid droplet formation, I am prouder of the work we have done on lipid trafficking and the oxysterol binding proteins. We struggled mightily for the first 15 years. At one point in 2015, I seriously considered abandoning this line of research. But we persisted and discovered their roles in regulating plasma membrane PI(4,5)P₂ and cholesterol, as well as in lipid droplet formation (3, 6).What has been the biggest challenge in your career so far?The biggest challenge has to do with the subject of my research topic: the fundamental cell biology of lipids. The sorting, distribution, and storage of cellular lipids are clearly very important topics in biology, but they are sometimes too fundamental to explain to funding agencies and new students. These days, lipid research is not as “sexy” as other topics. But there are so many unanswered questions in lipidology. I strongly believe that lipid research is going to be the next “big thing” as new techniques such as cryoEM now allow us to appreciate lipids and membrane proteins with unprecedented clarity.Who were your key influences early in your career?Besides mentors and teachers at Columbia, I really enjoyed reading and studying the works by Drs. Mike Brown and Joseph Goldstein, Ta-Yuan Chang, and Scott Emr. While they were not my teachers, their work inspired and impacted many young scientists, including me.What is the best advice you have been given?I have been given many pieces of great advice during my career. The best one in my view is “Less is more.” I was once told, “You would be better off with a lab of six than twelve.” Initially, I did not get it because I thought that a bigger group would allow me to explore more directions and be more productive. The reality is that, as a little-known junior researcher, few experienced people would join my laboratory. Funding is also a major limiting factor. Supervising a large number of students is fulfilling, but it also takes away some of my own time to think critically about the projects. I have largely kept my group under six, and this allows me to better supervise and guide the trainees. People say, “Once your team has more than 15 members, you become a manager instead of a scientist.” My own experience corroborates that statement because I struggled quite a bit when my group reached 12 at one point.What hobbies do you have?I am heavily into sports, especially basketball and tennis. I follow the NBA closely, and Jeremy Lin is my hero. I still play basketball at least twice a week. I am the captain of a basketball team comprised of scientists working on metabolism (see image). We play real, refereed basketball games against local teams during conferences. As I am getting older, I have also picked up tennis. I watch coaching videos on YouTube but still need a lot of work on my forehand. Through sports, I learned teamwork and the spirit of fighting to the last second. If I were not a scientist, I would probably run a sports-related business.What has been your biggest accomplishment outside of the laboratory?I got married and had children relatively early. Both of my kids are now in college and they appear to be decent human beings. I have been extremely lucky because my wife did most of the heavy lifting in looking after the kids. It was still a struggle for me to balance work and parental duties during the early days of my independent career. I am very proud and happy with where we are as a family right now.Any tips for a successful research career?Everyone is unique. Knowing your strengths and especially your weaknesses can be crucial to your success. My undergraduate training was in medicine and health management, and my PhD work focused on genetics and cell biology, so my understanding of physical chemistry is rather inadequate. I am also very bad at developing new methods. To alleviate these deficiencies, I constantly monitor new methods in my field and I purposefully look for collaborators with strong chemistry backgrounds. I have benefited immensely from such efforts.     

Gaia Pigino: Inside the cell

Gaia Pigino studies the molecular mechanisms and principles of self-organization in cilia using 3D cryo-EM.

Gaia Pigino was only 3 yr old when she became fascinated with nature in the beautiful countryside of Siena, Italy, where she grew up. The neighbor’s daughter showed her a hen in the chicken coop, and they caught it in the act of laying an egg. Gaia remembers, “This was for me almost a shock, as my experience about eggs was that they come directly out of paper boxes!” Her father was also an important part of awakening Gaia’s curiosity for the amazing things in nature. He used to bring home the award-winning magazine Airone, the Italian equivalent of National Geographic. Gaia never missed an issue; even before learning to read, she could spend hours looking at the captivating photos of the wildlife. She wanted to understand what she was seeing, and maybe because of that, she was determined to do science.Gaia Pigino. Photo courtesy of Human Technopole.Gaia took her first “scientific” steps with Professor Fabio Bernini and Professor Claudio Leonzio at the University of Siena, where she studied bioindicators of soil contamination and detoxification strategies of soil arthropods as part of her PhD project. But it was later, when she joined the laboratory of Professor Pietro Lupetti and met Professor Joel Rosenbaum, a pioneer of cilia research, that Gaia discovered the world of 3D EM and felt her place was “inside a single cell.” She solidified her interest in the structure of protein complexes of cilia and flagella and boosted her passion for cryo-electron tomography (ET) in the laboratory of Professor Takashi Ishikawa, first at the ETH Zurich and then at the Paul Scherrer Institut in Switzerland. In 2012, Gaia started her own laboratory at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany, with the vision of creating a truly interdisciplinary laboratory. Her team combines techniques from different fields such as biophysics, cell biology, and structural biology to answer open questions in the cilia field. Gaia recently moved countries again—this time to take over the position of Associate Head of the Structural Biology Research Centre, at the Human Technopole, Milan, Italy.We reached out to Gaia to learn more about her scientific journey and future research directions.What interested you about cilia?The first thing that attracted me toward cilia and flagella were some EM micrographs, by Professor Romano Dallai in Siena, that showed the beautiful geometrical microtubular structures of sperm flagella. I was intrigued by the apparent perfection of these organelles that clearly showed me that a cell is a coordinated system of complex molecular machines, the mechanism of many of which we do not understand. Soon after, Professor Joel Rosenbaum introduced me to the bidirectional transport of components inside cilia, which, he explained to me, is required for both assembly and function of virtually all cilia and flagella, from the motile cilia in our lungs to the primary cilium in our kidneys. He called it intraflagellar transport (IFT) and compared it to a Paternoster elevator, where the individual cabins were what we now call IFT trains. I was completely fascinated by the IFT system, the structure, the function, the dynamics, and the mechanism of which were still largely unknown. Quickly, I realized that in addition to IFT, cilia represent a virtually infinite source of open biological questions waiting to be solved, from the mechanics and regulation of the beating to the sensory function of primary cilia, and their importance for human health.What are some of the scientific questions currently of interest in your laboratory?In the past few years, we have made substantial contributions to the current understanding of the structure and the mechanism of the IFT (1, 2, 3). Currently, we are investigating how the structure of IFT trains relates to their functions by looking, in cryo-electron tomography, at how anterograde trains transform into retrograde trains and at how different ciliary cargoes are loaded on the trains. Beside this more classical line of research, we are exploring other approaches to study IFT, for instance we have developed a method to reactivate IFT trains in vitro on reconstituted microtubules. We want to use this approach to investigate the behavior of IFT trains, and their motors, in experimentally controllable conditions, e.g., in the presence of only certain tubulin posttranslational modifications. We have also made interesting discoveries about the distribution of tubulin posttranslational modifications on the microtubule doublets of the axoneme and how this spatially defined tubulin code affects the function of different ciliary components. We hope we will be able to share these new “stories” with the structural and cell biology community very soon!What kind of approach do you bring to your work?I believe that the main reason for why science became an integral, and dominant, part of my life is because it provides infinite riddles and continuous challenges. I have always been curious about how things work in nature, but I quickly realized that learning from books didn’t satisfy me. My desire was to be at the frontline, to be among the ones that see things happening in front of their eyes, at the microscope, for the first time. I wanted to be among the ones that make the discoveries that students read about in textbooks. Thus, what I bring to my work is an endless desire of solving biological riddles, curiosity, creativity, determination, and energy, with which I hope to inspire the members of my team. My laboratory uses an interdisciplinary approach; we use whatever method, technique or technology is needed to reach our goal, from the most basic tool to the most sophisticated cryo-electron microscope. And if the method we need does not yet exist, we try to invent it.A young Gaia Pigino (3 yr old) the day she discovered how eggs are made. Photo courtesy of Giancarlo Pigino.Could you tell us a bit about the Structural Biology Research Centre at the Human Technopole (HT)?At the HT Structural Biology Centre, we are working to create a vibrant and interdisciplinary scientific environment that will attract molecular, structural, cell, and computational biologists from all over the world. We are creating fantastic facilities, including one of the most well equipped and advanced electron microscopy facilities in Europe—and likely the world—headed by Paolo Swuec. My team, together with the teams of my colleague Alessandro Vannini and the research group leaders Ana Casañal, Francesca Coscia, and Philipp Erdmann, already cover a vast range of competences and know-how from classical molecular and structural biology approaches, such as crystallography and protein biophysics, to cryo-CLEM, cryo-FIB SEM and cryo-ET, all of which allow us to address questions in cell biology. Our goal is to create a scientific infrastructure and culture that will enable biologists to obtain a continuum of structural and functional information across scales.What did you learn during your PhD and postdoc that helped prepare you for being a group leader? What were you unprepared for?I learned that everyday research is mostly made of failures, but that with the right amount of obsession, persistence, curiosity, and creativity, it is always possible to succeed and discover new things. Being given the freedom to develop your own ideas and your own project very early in your career is a treat; science is not only about having good ideas! One needs to follow up on these ideas with intense work and troubleshooting to make them reality. In addition, I realized that being fearless and attempting what is considered too difficult by others, despite challenges, can turn into a worthy learning experience. Also, how you present your work to the scientific community matters for swinging the odds of success in your favor. Different places might work in very different ways, and conducting good science does not only depend on you, but also on the possibilities given to you by your environment.What was I unprepared for?—I guess several things, but one comes immediately to mind: I underestimated how much being responsible not only for my own life and career, but also the career of students, postdocs, and others in the laboratory, would affect me personally.Structure of the 96-nm axonemal repeat reconstructed by cryo-ET and subtomogram averaging. Image courtesy of Gonzalo Alvarez Viar, Pigino Lab.What has been the biggest accomplishment in your career so far?This is a tricky question for me... I tend to look into the future more than celebrating the past. I fight to succeed in something, but as soon as I conquer it, I find it less of an achievement than the thing I could conquer next. Nevertheless, I am happy about the discoveries and the papers published together with my students and postdocs (1, 2, 3, 4, 5). I am extremely excited about the fact that after many years of work I am now leading an interdisciplinary laboratory, where we combine techniques from different fields. I am also happy that three times my husband and I were able to move from one world class academic institution to the another to start exciting and fitting jobs and could still live together in the same place. We worked hard for this, but we also got lucky.What has been the biggest challenge in your career so far?I studied French in school; I had almost no exposure to spoken English until the end of my PhD. To avoid having to show my English insufficiencies, I did hide beside the board of my poster at the first international conference I attended in 2004! It took me a while to overcome this barrier and feel confident to express my thoughts and ideas in English.What do you think you would be if you were not a scientist?I had been a good fencer during my youth. I was a member of the Italian National Team between ages 14 and 19 and saw quite a bit of the world, which was cool! When my sporting career failed, due to diabetes, I was torn between art and science. I guess that in a parallel universe, I am a wildlife photographer and a potter specialized in wood kiln firing. [Gaia confesses that she misses “the amazing and addictive adrenaline rush of a good fencing match!”]Any tips for a successful research career?Do not compare your performances to the ones of the people at your career stage; compare yourself with people that are already successful one level higher than you currently are at. For example, if you are a PhD student, ask yourself what in your current performance separates you from being a good postdoc—once a postdoc, what is missing to be a good PI.     

From oxidative phosphorylation to transcription--a postdoctoral adventure

The period as a postdoctoral fellow is crucial for the establishment of one's scientific research career. I illustrate here its importance based on my own experience. Although luck played a part, moving to the right place at the right time and having generous leaders who allowed me freedom to express unconventional views were most valuable in my venture into two scientific territories that were previously unfamiliar to me. My first encounter with an unknown field led to me challenging the well-established dogma of uncoupling of oxidative phosphorylation as the explanation for hormone action; the second, led to the demonstration of the multiplicity of eukaryotic RNA polymerase. I hope that the events described here will provide some encouragement to young scientists embarking on a research career and also be of interest to others.     

Another decade of advances in research on primary cilia,porosomes and neosis: Some passing thoughts at 70

This editorial contains some of my reflections on a career spanning almost 50 years in biomedical research at the cellular level and over 12 years as Editor‐in‐Chief of Cell Biology International, at the time of my 70th birthday. It is gratifying that I have been involved in some of the more important organelles and processes that have come to the forefront of cell research today, and I have chosen just three examples to illustrate this point.     

A question of taste

A career in science is shaped by many factors, one of the most important being our tastes in research. These typically form early and are shaped by subsequent successes and failures. My tastes run to microscopes, chemistry, and spatial organization of cytoplasm. I will try to identify where they came from, how they shaped my career, and how they continue to evolve. My hope is to inspire young scientists to identify and celebrate their own unique tastes.     

(M,R)-systems, (P,M,C)-nets, hierarchical decay, and biological aging: reminiscences of Robert Rosen

I have the pleasure to present a number of personal experiences that I had with Robert Rosen, both as his student and as a research colleague, and I will describe how this affected my academic career over the past decades. As a matter of fact, Rosen's work with (M,R)-systems as well as his continuing mentorship guided me into my own research in gerontology and geriatrics. Amazingly, this still continues to affect my work in complexity theory after 30 years.     

Nouvel essai de classification et de structuration des motifs des gravures rupestres du Haut Atlas (vallée de l'Ourika, Maroc)

We have been sometimes forced to notice that there are forgotten rupestral arts: until recently, they were only studied by explorers or informed travellers and are rarely reported in the scientific literature. This is in part the case of engravings in the Moroccan High Atlas to which I have devoted my research (Ezziani, 2002, 2004a, 2004b). J Malhomme is among the people who were most invested in their investigation. He spent ten years in noting and collecting a considerable number of engravings: more than one thousand figures dispersed on the sides of the Atlas in places of difficult access at more than 2000 masl. He published many papers about his discoveries, which led to the publication of a remarkable corpus in two parts (Malhomme, 1959-1961). However, this corpus is far from being exhaustive. Recently, A. Rodrigue carried out new and excellent drawings within his research activity (1996). He added to the corpus of Malhomme a large number of figures discovered by A. Simoneau (1967, 1968, 1970), A. Jodin (1964, 1966) (two other researchers who have been closely interested in the High Atlas engravings) and himself, but unfortunately some engravings were damaged: whole flagstones have disappeared, so that the original drawings from Malhomme still remain very useful. All these data constituted the documentation base of my own work. In this paper, first I review some classification methods, then I propose my own and point out the inherent difficulties in this task. I conclude with a proposal for an outline of the structure of the High Atlas engravings.     

Balancing teaching and research experiences in doctoral training programs: lessons for the future educator

While a variety of alternative careers has emerged for Ph.D. life scientists in industry, business, law, and education in the past two decades, the structure of doctoral training programs in many cases does not provide the flexibility necessary to pursue career experiences not directly related to a research emphasis. Here I describe my efforts to supplement my traditional doctoral research training with independent teaching experiences that have allowed me to prepare myself for a career that combines both into a combined educational program. I describe the issues I have come across in finding and taking part in these endeavors, how these issues have affected my work in pursuing my Ph.D., and how my experiences translate into my hopes for a future education-based career in molecular and cell biology.     

The wanderings of a free radical

In my career I have moved from chemistry to biochemistry to plant science to clinical chemistry and back again (in a partial way) to plants. This review presents a brief history of my research achievements (ascorbate–glutathione cycle, role of iron in oxidative damage and human disease, biomarkers of free radical damage, and studies on atherosclerosis and neurodegeneration) and how they relate to my research activities today. The field of free radicals/other reactive species/antioxidants underpins all of modern Biology. These agents helped to drive human evolution and the basic principles of the field are repeatedly found to be relevant in other research areas. It was an exciting field when I started some 40 years ago, and it still is today, but some major challenges must be faced.     

Chance and serendipity in science: two examples from my own career

The usual scientific paper follows a rather narrowly (but not ever rigidly) defined pattern. Both the author and the journal like to see a linear logical presentation of a "story." Seldom does the paper give the reader the "backstory." Where did the idea come from in the first place? How many false leads led down blind alleys? What happened by chance and what by logical planning? Was there an element of serendipity involved? Perhaps as we enter the paperless era and do not have to count words quite so religiously, it may be possible to encourage a more freewheeling scientific paper, but for now, we have to rely on the historians of science and/or those who "tell all" about their own research. "Reflections" seems an appropriate space for the latter. I have chosen two scenarios from my own career in which happy accidents played important roles but, unhappily, received little recognition in my published papers.