Raman spectroscopic study on structure of human immunodeficiency virus (HIV) and hypericin-induced photosensitive damage of HIV

Viruses are agents of some of the most destruc- tive diseases afflicting plants and animals[1]. Viruses also play a central role in experimental methods of molecular and cellular biology, especially in modern genetic engineering[1]. Raman spectroscopy is a pow-erful tool for studying the structure of the whole virion. A number of researches are limited to the conforma-tion of viruses, involving only nucleic acid (RNA or DNA) and its coat protein[1]. Literatures can be found concerning Raman…     

Herpes Simplex Virus 1 Infection Alters the mRNA Translation Processing in L-02 Cells

HSV-1 infection-mediated regulation of mRNA translation in host cells is a systematic and complicated process. Investigation of the details of this mechanism will facilitate understanding of biological variations in the viral replication process and host cells. In this study, a comparative proteomics technology platform was applied by two-dimension electrophoresis of HSV-1 infected normal human L-02 cell and control cell lysates. The observed protein spots were analyzed qualitatively and quantitatively by the PDQuest software package. A number of the different observed protein spots closely associated with cellular protein synthesis were identified by matrix-assisted laser-desorption ionization-time of flight-mass spectrometry （MALDI-TOF-MS）. The expression levels of the RPLP1 protein, which is required for mRNA translation, and KHSRP protein, which is involved in rapid decay of mRNA, were up-regulated, whereas the expression level of RNP H2, which is involved in positive regulation on the mRNA splicing process, was down-regulated. All of these results suggest that HSV-1 infection can influence cellular protein synthesis via modulation of cellular regulatory proteins involved in RNA splicing, translation and decay, resulting in optimisation of viral protein synthesis when cellular protein synthesis is shut off Although there is need for further investigations regarding the detailed mechanisms of cellular protein control, our studies provide new insight into the targeting of varied virus signaling pathways involved in host cellular protein synthesis.     

Ubiquitination-mediated protein degradation and modification： an emerging theme in plant-microbe interactions

Post-translational modification is central to protein stability and to the naodulation of protein activity.Various types ofprotein modification,such as phosphorylation,methylation,acetylation,myristoylation,glycosylation,and ubiquitina-tion,have been reported.Among them,ubiquitination distinguishes itself from others in that most of the ubiquitinatedproteins are targeted to the 26S proteasome for degradation.The ubiquitin/26S proteasome system constitutes the majorprotein degradation pathway in the cell.In recent years,the importance of the ubiquitination machinery in the controlof numerous eukaryotic cellular functions has been increasingly appreciated.Increasing number of E3 ubiquitin ligasesand their substrates,including a variety of essential cellular regulators have been identified.Studies in the past severalyears have revealed that the ubiquitination system is important for a broad range of plant developmental processes andresponses to abiotic and biotic stresses.This review discusses recent advances in the functional analysis of ubiquitina-tion-associated proteins from plants and pathogens that play important roles in plant-microbe interactions.     

Interactions of the HSV-1 UL25 Capsid Protein with Cellular Microtubule-associated Protein

An interaction between the HSV-1 UL25 capsid protein and cellular microtubule-associated protein was found using a yeast two-hybrid screen and β-D-galactosidase activity assays. Immunofluorescence microscopy of the UL25 protein demonstrated its co-localization with cellular microtubule-associated protein in the plasma membrane. Further investigations with deletion mutants suggest that UL25 is likely to have a function in the nucleus.     

Protein engineering of a fibroblast growth factor-1 fusion protein with cell adhesive activity

Fibroblast growth factor-1 （FGF1） is one of the most potent angiogenic growth factors, and also plays an important role in regulating cellular functions including cell proliferation, motility, differentiation, survival, and tissue regeneration processes. Here we described a novel fusion protein that was designed by combining the cell adhesion sequence from fibronectin with FGF1. The F1-Fn fusion protein functions as a minimized protein that directs integrin-dependent cell adhesion and stimulates cellular responses including cell proliferation and differentiation. Moreover, our results indicate that Fn-mediated signaling synergizes with signals from FGF1 in promoting cellular adhesion, proliferation, and differentiation in MG63 cells.     

Effect of DNA binding protein Sshl2 from hyperthermophilic archaeon Sulfolobus shibatae on DNA supercoiling

An 11.5-ku DNA binding protein, designated as Sshl2, was purified from the hyperthermophilic archaeon Sulfolobus shibatae by column chromatography in SP Sepharose, DNA cellulose and phosphocellulose. Sshl2 accounts for about 4 % of the total cellular protein. The protein is capable of binding to both negatively supercoiled and relaxed DNAs. Nick closure analysis revealed that Sshl2 constrains negative supercoils upon binding to DNA. While the ability of the protein to constrain supercoils is weak at 22℃ , it is enhanced substantially at temperatures higher than 37℃ . Both the cellular content and supercoil-constraining ability of Sshl2 suggest that the protein may play an important role in the organization and stabilization of the chromosome of S. shibatae.     

Effect of DNA binding protein Sshl2 from hyperthermophilic archaeon Sulfolobus shibatae on DNA supercoiling

An 11.5-ku DNA binding protein, designated as Sshl2, was purified from the hyperthermophilic archaeon Sulfolobus shibatae by column chromatography in SP Sepharose, DNA cellulose and phosphocellulose. Sshl2 accounts for about 4 % of the total cellular protein. The protein is capable of binding to both negatively supercoiled and relaxed DNAs. Nick closure analysis revealed that Sshl2 constrains negative supercoils upon binding to DNA. While the ability of the protein to constrain supercoils is weak at 22℃ , it is enhanced substantially at temperatures higher than 37℃ . Both the cellular content and supercoil-constraining ability of Sshl2 suggest that the protein may play an important role in the organization and stabilization of the chromosome of S. shibatae.     

High-resolution 3D structures reveal the biological functions of reoviruses

Viruses in the family Reoviridae are non-enveloped particles comprising a segmented double-stranded RNA genome surrounded by a two-layered or multi-layered icosahedral protein capsid. These viruses are classified into two sub-families based on their particle structural organization. Recent studies have focused on high-resolution three-dimensional structures of reovirus particles by using cryo-electron microscopy （cryo-EM） to approach the resolutions seen in X-ray crystallographic structures. The results of cryo-EM image reconstructions allow tracing of most of the protein side chains, and thus permit integration of structural and functional information into a coherent mechanism for reovirus assembly and entry.     

Immediate–Early(IE) gene regulation of cytomegalovirus:IE1-and pp71-mediated viral strategies against cellular defenses

Three crucial hurdles hinder studies on human cytomegalovirus(HCMV): strict species specificity, differences between in vivo and in vitro infection, and the complexity of gene regulation. Ever since the sequencing of the whole genome was first accomplished, functional studies on individual genes have been the mainstream in the CMV field. Gene regulation has therefore been elucidated in a more detailed fashion. However, viral gene regulation is largely controlled by both cellular and viral components. In other words, viral gene expression is determined by the virus–host interaction. Generally, cells respond to viral infection in a defensive pattern; at the same time, viruses try to counteract the cellular defense or else hide in the host(latency). Viruses evolve effective strategies against cellular defense in order to achieve replicative success. Whether or not they are successful, cellular defenses remain in the whole viral replication cycle: entry, immediate–early(IE) gene expression, early gene expression, DNA replication, late gene expression, and viral egress. Many viral strategies against cellular defense, and which occur in the immediate–early time of viral infection, have been documented. In this review, we will summarize the documented biological functions of IE1 and pp71 proteins, especially with regard to how they counteract cellular intrinsic defenses.     

Golgi localization and dynamics of hyaluronan binding protein 1 （HABP1／p32／C1QBP） during the cell cycle

Hyaluronan binding protein 1 (HABP1) is a negatively charged multifunctional mammalian protein with a unique structural fold. Despite the fact that HABP1 possesses mitochondrial localization signal, it has also been localized to other cellular compartments. Using indirect immunofluorescence, we examined the sub-cellular localization of HABP1 and its dynamics during mitosis. We wanted to determine whether it distributes in any distinctive manner after mitoticnuclear envelope disassembly or is dispersed randomly throughout the cell. Our results reveal the golgi localization of HABP1 and demonstrate its complete dispersion throughout the cell during mitosis. This distinctive distribution pattern of HABP1 during mitosis resembles its ligand hyaluronan, suggesting that in concert with each other the two molecules play critical roles in this dynamic process.     

PII,the key regulator of nitrogen metabolism in the cyanobacteria

PII proteins are a protein family important to signal transduction in bacteria and plants. PII plays a critical role in regulation of carbon and nitrogen metabolism in cyanobacteria. Through conformation change and covalent modification, which are regulated by 2-oxoglutarate, PII interacts with different target proteins in response to changes of cellular energy status and carbon and nitrogen sources in cyanobacteria and regulates cellular metabolism. This article reports recent progress in PII research in cyanobacteria and discusses the mechanism of PII regulation of cellular metabolism .     

Polyomavirus interaction with the DNA damage response

Viruses are obligate intracellular parasites that subvert cellular metabolism and pathways to mediate their own replication—normally at the expense of the host cell. Polyomaviruses are a group of small DNA viruses, which have long been studied as a model for eukaryotic DNA replication. Polyomaviruses manipulate host replication proteins, as well as proteins involved in DNA maintenance and repair, to serve as essential cofactors for productive infection. Moreover, evidence suggests that polyomavirus infection poses a unique genotoxic threat to the host cell. In response to any source of DNA damage, cells must initiate an effective DNA damage response(DDR) to maintain genomic integrity, wherein two protein kinases, ataxia telangiectasia mutated(ATM) and ATM- and Rad3-related(ATR), are major regulators of DNA damage recognition and repair. Recent investigation suggests that these essential DDR proteins are required for productive polyomavirus infection. This review will focus on polyomaviruses and their interaction with ATMand ATR-mediated DNA damage responses and the effect of this interaction on host genomic stability.     

Ran binding protein 9(RanBPM) binds IFN-λR1 in the IFN-λsignaling pathway

Like the type I interferons(IFNs),the recently discovered cytokine IFN-λ displays antiviral,antiproliferative,and proapoptotic activities,mediated by a heterodimeric IFN-λ receptor complex composed of a unique IFN-λR1 chain and the IL-10R2 chain.However,the molecular mechanism of the IFN-λ-regulated pathway remains unclear.In this study,we newly identified RAN-binding protein M(RanBPM) as a binding partner of IFN-λR1.The interaction between RanBPM and IFN-λRl was identified with a glutathione S-transferase pull-down assay and coimmunoprecipitation experiments.IFN-λ1 stimulates this interaction and affects the cellular distribution of RanBPM.However,the interaction between RanBPM and IFN-λR1 does not correlate with their conserved TRAF6-binding sites.Furthermore,we also found that RanBPM is a scaffolding protein with a modulatory function that regulates the activities of IFN-stimulated response elements.Therefore,RanBPM plays a novel role in the IFN-λ-regulated signaling pathway.     

PINK1 is involved in determining the cellular autophagic hierarchy

<正>The protein PINK1 plays a crucial role in the regulation of the cellular autophagic hierarchy. Autophagy, a highly conserved biological process, serves as a mechanism for the degradation of intracellular components by lysosomes. Autophagosomes play a pivotal role in this process by selectively sequestering specific targets, including damaged organelles,protein aggregates, and pathogens.     

The Chloroplast Kinase Network： New Insights from Large-Scale Phosphoproteome Profiling

Protein phosphorylation is one of the most important posttranslational modifications in eukaryotic cells and affects almost all basic cellular processes. The chloroplast as plant-specific cell organelle with important metabolic functions is integrated into the cellular signaling and phosphorylation network. Recent large-scale chloroplast phosphoproteome analyses in Arabidopsis have provided new information about phosphorylation targets and expanded the list of chloroplast metabolic and regulatory functions that are potentially controlled by protein phosphorylation. Phosphorylated peptides identified from chloroplast proteins provide new insights into phosphorylation motifs, protein kinase activities, and substrate utilization. Phosphorylation sites in protein kinases can reveal chloroplast phosphorylation cascades that may network different functions by integrating signaling chains. Our review provides a meta-analysis of currently available chloroplast phosphoproteome information and discusses biological insights from large-scale chloroplast phosphoprotein profiling as well as technological constraints of kinase network analysis.     

Control of grain size by G protein signaling in rice

Heterotrimeric G proteins are involved in multiple cellular processes in eukaryotes by sensing and transducing various signals. G protein signaling in plants is quite different from that in animals, and the mechanisms of plant G protein signaling are still largely unknown. Several recent studies have provided new insights into the mechanisms of G protein signaling in rice grain size and yield control. In this review,we summarize recent advances on the function of G proteins in rice grain size control and discuss the potential genetic and molecular mechanisms of plant G protein signaling.     

MAPK signal pathways in the regulation of cell proliferation in mammalian cells

INTRODUCTIONMitogen-activated protein kinaJse (MAPK) cas-cades have been shown to play a key role in trans-duction extracellular signals to cellular responses. Inmammalian cells, three MAPK families have beenclearly characterized: namely classical MAPK (alsoknown as ERK), C-Jun N-terminal kinse/ stress-activated protein kinase (JNK/SAPK) and p38 ki-nase. MAP kinases lie within protein kinase cas-cades. Each cascade consists of no fewer than threeenzymes that are activated in se…