FHA domain pThr binding specificity: it's all about me

The FHA domain is a phospho-peptide binding module involved in a wide range of cellular pathways, with a striking specificity for phospho-threonine over phospho-serine binding partners. Biochemical, structural, and dynamic simulations analysis allowed Pennell and colleagues to unravel the molecular basis of FHA domain phospho-threonine specificity.     

Generating a Wnt switch: it's all about the right dosage

Wnt proteins can activate different branches of the Wnt signaling pathway, raising the question of specificity. In this issue, Nalesso et al. (2011. J. Cell Biol. doi:10.1083/jcb.201011051) provide an answer to this conundrum by showing that different concentrations of Wnt ligands can elicit different intracellular responses. These findings not only provide new insights into the molecular mechanisms underlying Wnt signaling, but also indicate how Wnt gradients might contribute to tissue patterning during embryogenesis.     

Plant cell responses to cold are all about timing

Changes in temperature present the cells of plants with particular challenges. Fortunately, many changes in temperature can be anticipated due to the rhythms of day/night and the seasons. To anticipate changes in the environment most organisms have a circadian clock to optimize daily and seasonal timing of gene expression, metabolism, physiology and cell biology. Circadian clocks comprised positive and negative feedback loops which ensure an internal period of approximately 24 hours. We describe the role of the circadian clock in modulating cellular cold signalling networks to prepare the cell for the onset of winter.     

What is all the noise about in interval timing?

Cognitive processes such as decision-making, rate calculation and planning require an accurate estimation of durations in the supra-second range—interval timing. In addition to being accurate, interval timing is scale invariant: the time-estimation errors are proportional to the estimated duration. The origin and mechanisms of this fundamental property are unknown. We discuss the computational properties of a circuit consisting of a large number of (input) neural oscillators projecting on a small number of (output) coincidence detector neurons, which allows time to be coded by the pattern of coincidental activation of its inputs. We showed analytically and checked numerically that time-scale invariance emerges from the neural noise. In particular, we found that errors or noise during storing or retrieving information regarding the memorized criterion time produce symmetric, Gaussian-like output whose width increases linearly with the criterion time. In contrast, frequency variability produces an asymmetric, long-tailed Gaussian-like output, that also obeys scale invariant property. In this architecture, time-scale invariance depends neither on the details of the input population, nor on the distribution probability of noise.     

Hox Genes: it's all a matter of context

Recent studies provide compelling new evidence that Hox gene effects depend on fine-structure spatial and temporal information. Further, in a specific cell type, only one or a few downstream genes may mediate Hox morphogenetic functions. If this is generally true, it will have important implications for how Hox regulatory networks operate and evolve.     

In the end, it's all structure

Chromosome end protection is essential for all organisms with linear genomes. Specialized structures, called telomeres, accomplish this protection by forming DNA-protein complexes that hide the natural chromosome ends from the DNA damage machinery. In mammalian cells protection takes place on several levels. Telomeric DNA forms large duplex loops with the help of telomeric proteins, consequently hiding the very tip of the telomere. Telomeric proteins play additional roles in protecting the end from degradation, regulating telomere length, and suppressing the DNA damage response machinery. Here we summarize the current knowledge about telomere structure, and discuss the future directions of the field.     

The complex relationship between mycobacteria and macrophages: it's not all bliss

Mycobacteria are uniquely adapted to grow inside host macrophages. As Clay et al. show in this issue of Cell Host & Microbe and as van der Wel et al. show in a recent issue of Cell, there are both benefits and drawbacks for the pathogen in adopting this strategy, and some of our fundamental assumptions about how the host cell and bacterium interact might need to be reexamined.     

Metabolic reprogramming in response to cold stress is like real estate,it's all about location

This article comments on: Subcellular reprogramming of metabolism during cold acclimation in Arabidopsis thaliana     

Genetic response to rapid climate change: it's seasonal timing that matters

The primary nonbiological result of recent rapid climate change is warming winter temperatures, particularly at northern latitudes, leading to longer growing seasons and new seasonal exigencies and opportunities. Biological responses reflect selection due to the earlier arrival of spring, the later arrival of fall, or the increasing length of the growing season. Animals from rotifers to rodents use the high reliability of day length to time the seasonal transitions in their life histories that are crucial to fitness in temperate and polar environments: when to begin developing in the spring, when to reproduce, when to enter dormancy or when to migrate, thereby exploiting favourable temperatures and avoiding unfavourable temperatures. In documented cases of evolutionary (genetic) response to recent, rapid climate change, the role of day length (photoperiodism) ranges from causal to inhibitory; in no case has there been demonstrated a genetic shift in thermal optima or thermal tolerance. More effort should be made to explore the role of photoperiodism in genetic responses to climate change and to rule out the role of photoperiod in the timing of seasonal life histories before thermal adaptation is assumed to be the major evolutionary response to climate change.     

For Parkin,it's not all or nothing

Mitochondria accumulate damage over time, which can lead to impairment of cell function by excessive production of reactive oxygen species. The PINK1/Parkin pathway therefore monitors the quality of the mitochondrial population and stimulates the elimination of depolarized organelles by mitophagy. In this issue of The EMBO Journal, McLelland et al ( 2014 ) show that this pathway also responds to mild oxidative damage, and instead of inducing mitophagy, allows oxidized proteins to be sorted into mitochondria‐derived vesicles (MDVs) that are transported to lysosomes.     

Standardizing digital photography: it's not all in the eye of the beholder

Advances in digital photography have made it an efficient and economically appealing alternative to conventional photography. Nevertheless, as objective observers and clinical photographers, we must realize that all digital cameras are not created equal. Different digital cameras frequently used in plastic surgery practices (Olympus 600DL, Olympus 2500, Sony DSC-D700, Nikon Coolpix 950, and Nikon D1) were evaluated, using a subject photographed with each camera in the identical lighting conditions, to determine inherent differences in quality, color, and contrast of the resultant photographs. Three different lighting conditions were examined: single soft-box lighting, dual studio flash boxes, and operating room lighting with on-camera flash. The same digital settings (program mode, ISO camera default setting, high quality setting with JPEG compression) were used. Each camera was digitally color balanced using an 18 percent gray card. Raw and color-balanced images were viewed side-by-side. The macro-image capabilities of each camera were also examined. Conventional 35-mm photographs using a 105 macro-lens on Kodachrome and Ektachrome slide film were obtained for comparison. All of the digital cameras performed with noticeable differences, but they maintained consistency in the three different lighting conditions. Digital photographs differed most greatly with respect to quality and contrast, which was especially obvious once color balancing was performed. Marked differences in quality and ability were observed with respect to macro-image capabilities. Inherent differences in features among digital cameras produce dramatically different photographic results with regard to color, contrast, focus, and overall quality. With the increasing use of digital photography in plastic surgery journals and presentations, it must be recognized that digital cameras do not all display photographs of similar quality, especially when used to evaluate skin appearance. To standardize digital photography, the surgeon must realize that switching digital cameras is akin to switching film types. Standardization of digital photographs should include image resolution between 1.5 and 2.7 million pixels, ISO default setting, color balancing with an 18 percent gray card and software, consistency in focal distance, JPEG compression of medium-to-high quality, and backgrounds of medium blue or 18 percent gray.