Eric Karsenti

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..The Tara Oceans consortium organizes expeditions to help fill this gap at the global level...

..We wonder in this respect whether lower eukaryotes such as yeasts are different from higher eukaryotes such as vertebrates...

..We illustrate how this led to the beginning of an understanding of dynamic cellular patterns that have precise functions...

..Self-organization concepts that were first developed in chemistry and physics and then applied to various morphogenetic problems in biology over the past century are now beginning to be applied to the organization of the living cell...

..Our results indicate that Cdk11 is responsible for RanGTP-dependent MT stabilization around chromosomes and that this local stabilization is essential for normal rates of spindle assembly and spindle function...

..Our data indicate that HURP and TPX2 have nonredundant functions essential for chromatin-induced microtubule assembly...

..We propose a reaction-diffusion model that combines the chromosome generated Ran-guanosine triphosphate-Importin reaction network to a secondary phosphorylation network as a potential mechanism for the generation of such gradients...

..Our results demonstrate that distinctly from its role in spindle assembly, RanGTP maintains spindle MTs in anaphase through the local activation of ISWI and that this is essential for proper chromosome segregation...

..This produces activity gradients that determine the spatial distribution of microtubule nucleation and stabilization around chromosomes and that are essential for the self-organization of microtubules into a bipolar spindle...

..These and previous results suggest that under physiological conditions, TPX2 is essential for microtubule nucleation around chromatin and functions in a network of other molecules, some of which also are regulated by RanGTP...

..Therefore, the XMAP215-EB1 interaction is required for proper spindle organization and chromosome segregation in Xenopus egg extracts...

..We argue that such reaction diffusion processes are involved in the self-organization of supramolecular structures in the cell...

..These interaction patterns are likely to reflect phosphorylation of stathmin in these areas...

..Our results show that chromatin defines spindle shape and orientation. For a video summary of this article, see the PaperFlick file available with the online Supplemental Data...

..This provides the beginning of a biochemical description of the notion of "cytoplasmic states" regarding the microtubule system...

..elegans. The diverse roles of these two proteins in spindle assembly leave us to beckon the true C. elegans TPX2 ortholog to center stage...

..This indicates that chromosome-induced microtubule production is a general requirement for the formation of functional spindles in animal cells...

..MURF2 can therefore act as a transient adaptor between microtubules, titin and nascent myosin filaments, as well as being involved in signalling from the sarcomere to the nucleus...

..Together, these observations suggest that the spindle can be experimentally deconstructed, and that its defining characteristics can be studied in a simplified context, in the absence of the full division machinery...

..To our knowledge, this is the first direct evidence of a long-range guidance effect at the sub-cellular level...

..The data suggest that the critical early function in spindle formation regulated by importin alpha is TPX2-mediated microtubule nucleation...

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..Two related MAPs, XMAP215 and Stu2p, are known to stabilize MTs. However, recent studies report that these proteins have a MT-destabilizing function as well. Here we discuss the implications of these reports...

..These results suggest that Eg5 is responsible for flux-associated MT translocation and that dynein and Xklp2 regulate flux-associated microtubule depolymerization at spindle poles...

..These findings were made possible due to the application of sequence-similarity methods, which extended mass spectrometric protein identification capabilities by 2-fold compared to conventional methods...

..Collectively, our results strongly suggest that MTs become organized into a scaffold that provides directional cues for the positioning and organization of myosin filaments during sarcomere formation...

..It has the potential to be extended to study interactions of proteins or multi-protein complexes with different biopolymers like actin microfilaments or organelle membranes...