Right time - right location - right move: TRPs find motors for common functions

TRP channels are localized at specialized sub-cellular compartments like filopodial tips, ciliary structures, growth cones and spines that have importance in the context of several sensory functions. Several motor proteins largely regulate these localizations. Recent studies indicate that both physical and genetic interactions exist between TRP channels with actin and microtubule-based motor proteins. These two groups of proteins share specialized and fine regulation underlying physiological functions. Indeed, mutations causing loss of these interactions and regulations result in development of pathophysiological disorders and syndromes. In this review we analyze the recent progress made in cell-biological, biochemical, electrophysiological and genetic studies and summarize the multi-dimensional crosstalk between TRP channels with different motor proteins.     

Being in the right location at the right time

Taking each coding sequence from the human genome in turn and identifying the subcellular localization of the corresponding protein would be a significant contribution to understanding the function of each of these genes and to deciphering functional networks. This article highlights current approaches aimed at achieving this goal.     

Right place,right time - Spatial guidance of neuronal morphogenesis by septin GTPases

Neuronal morphogenesis is guided by outside-in signals and inside-out mechanisms, which require spatiotemporal precision. How the intracellular mechanisms of neuronal morphogenesis are spatiotemporally controlled is not well understood. Septins comprise a unique GTPase module, which consists of complexes with differential localizations and functions. Septins demarcate distinct membrane domains in neural precursor cells, orienting the axis of cell division and the sites of neurite formation. By controlling the localization of membrane and cytoskeletal proteins, septins promote axon-dendrite formation and polarity. Furthermore, septins modulate vesicle exocytosis at pre-synaptic terminals, and stabilize dendritic spines and post-synaptic densities in a phospho-regulatable manner. We posit that neuronal septins are topologically and functionally specialized for the spatiotemporal regulation of neuronal morphogenesis and plasticity.     

Right place,right time: Spatiotemporal light regulation of plant growth and development

Recent advances in our understanding of the roles of photoreceptors in light-dependent regulation of plant growth and development have been rapid and significant. Developments have been reported for numerous plant photoreceptor signaling pathways, yet researchers have made the most progress in increasing our comprehension of the roles of phytochrome family members, as well as the intracellular roles of phytochromes and phytochrome-interacting proteins in light-dependent signaling. An understudied, but vitally important, area of phytochrome biology centers on the roles phytochromes play in intercellular and interorgan signaling at the molecular level that results in the coordination of growth responses between distinct tissues and organs. This frontier of research into the spatiotemporal roles of phytochromes, and more generally plant photoreceptors, which is only beginning to be investigated and understood at the molecular genetic level, has a rich history of physiological data.Key words: cryptochrome, photomorphogenesis, photoreception, photoreceptor, phytochrome, spatiotemporal     

Microtubules, motors, and mRNA localization mechanisms: watching fluorescent messages move.

Proper spatial and temporal localization of specific mRNAs is pivotal in the early stages of development. To dissect the mechanisms of localization, several groups are employing advanced fluorescence microscopy to track RNA movements in live oocytes and embryos.     

Mitotic functions of the Ran GTPase network: the importance of being in the right place at the right time

The Ran GTPase has important roles in nucleocytoplasmic transport, cell cycle progression, nuclear organization and nuclear envelope (NE) assembly. In this review, we discuss emerging evidence that implicate the Ran GTPase system in mitotic control in mammalian cells. Recent work indicates that members of the Ran network control two fundamental aspects of the mammalian mitotic apparatus: (i) centrosome and spindle pole function, and (ii) kinetochore function. It is also emerging that, after NE breakdown, specific Ran network components assemble in local combinations at crucial sites of the mitotic apparatus. In the light of these findings, the original notion that nucleotide-bound forms of the Ran GTPase are distributed along a unique "gradient" in mitotic cells should be re-examined. Available data also suggest that the Ran system is deregulated in certain cellular contexts: this may represent a favoring condition for the onset and propagation of mitotic errors that can predispose cells to become genetically unstable and facilitate neoplastic growth.     

New anthelmintics for livestock: the time is right

The viability of small-ruminant enterprises is under threat in some locations because anthelmintic resistance continues to increase in prevalence and severity. Despite this, no new anthelmintic group has been developed for many years, and animal health companies seem unconvinced of the commercial justification for new compounds for the ruminant market. It is now argued, however, that market conditions are becoming favourable because of increases in multiple-drug resistance in nematodes of ruminants and other hosts and because few non-chemical options exist. A new anthelmintic is urgently needed and will find ready acceptance in an increasing market, and with better knowledge of resistance management, greater product longevity can be achieved.     

Visual function: how spiders find the right rock to crawl under

Animals that go on hunting expeditions face the problem of finding the way home at the end of the day. A group of hunting spiders has now been added to the list of animals that use the celestial pattern of polarized light as a compass to navigate with, and explains an old conundrum of spider eye anatomy.     

Why cells move messages: the biological functions of mRNA localization

RNA localization is a widespread mechanism that allows cells to spatially control protein function by determining their sites of synthesis. In embryos, localized mRNAs are involved in morphogen gradient formation or the asymmetric distribution of cell fate determinants. In somatic cell types, mRNA localization contributes to local assembly of protein complexes or facilitates protein targeting to organelles. Long-distance transport of specific mRNAs in plants allows coordination of developmental processes between different plant organs. In this review, we will discuss the biological significance of different patterns of mRNA localization.     

Plants on the move: Towards common mechanisms governing mechanically-induced plant movements

One may think that plants seem relatively immobile. Nevertheless, plants not only produce movement but these movements can be quite rapid such as the closing traps of carnivorous plants, the folding up of leaflets in some Leguminosae species and the movement of floral organs in order to increase cross pollination. We focus this review on thigmotropic and thigmonastic movements, both in vegetative and reproductive parts of higher plants. Ultrastructural studies revealed that most thigmotropic and thigmonastic movements are caused by differentially changing cell turgor within a given tissue. Auxin has emerged as a key molecule that modulates proton extrusion and thus causing changes in cell turgor by enhancing the activity of H⁺ATPase in cell membranes. Finding conserved molecules and/or operational molecular modules among diverse types of movements would help us to find universal mechanisms controlling movements in plants and thus improve our understanding about the evolution of such phenomena.