title: MAP65/Ase1 promote microtubule flexibility.
abstract: Microtubules (MTs) are dynamic cytoskeletal elements involved in numerous cellular processes. Although they are highly rigid polymers with a persistence length of 1-8 mm, they may exhibit a curved shape at a scale of few micrometers within cells, depending on their biological functions. However, how MT flexural rigidity in cells is regulated remains poorly understood. Here we ask whether MT-associated proteins (MAPs) could locally control the mechanical properties of MTs. We show that two major cross-linkers of the conserved MAP65/PRC1/Ase1 family drastically decrease MT rigidity. Their MT-binding domain mediates this effect. Remarkably, the softening effect of MAP65 observed on single MTs is maintained when MTs are cross-linked. By reconstituting physical collisions between growing MTs/MT bundles, we further show that the decrease in MT stiffness induced by MAP65 proteins is responsible for the sharp bending deformations observed in cells when they coalign at a steep angle to create bundles. Taken together, these data provide new insights into how MAP65, by modifying MT mechanical properties, may regulate the formation of complex MT arrays.
authors.affiliation: Laboratoire de Physiologie Cellulaire et Végétale, Institut de Recherches en Technologies et Sciences pour le Vivant, UMR CNRS, CEA, INRA, Université Joseph Fourier, 38054 Grenoble, France.
authors.forename: D
authors.initials: D
authors.lastname: Portran
authors.forename: M
authors.initials: M
authors.lastname: Zoccoler
authors.forename: J
authors.initials: J
authors.lastname: Gaillard
authors.forename: V
authors.initials: V
authors.lastname: Stoppin-Mellet
authors.forename: E
authors.initials: E
authors.lastname: Neumann
authors.forename: I
authors.initials: I
authors.lastname: Arnal
authors.forename: J L
authors.initials: JL
authors.lastname: Martiel
authors.forename: M
authors.initials: M
authors.lastname: Vantard
mesh_terms: D000465:Algorithms; D000818:Animals; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D002417:Cattle; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000737:chemistry* / Q000378:metabolism; D008954:Models, Biological; D008956:Models, Chemical; D008958:Models, Molecular; D018583:Pliability; D011993:Recombinant Fusion Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D059008:Time-Lapse Imaging; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C492901:MAP65-1 protein, Arabidopsis; C557480:MAP65-4 protein, Arabidopsis; D008869:Microtubule-Associated Proteins; D011993:Recombinant Fusion Proteins; D014404:Tubulin; D049452:Green Fluorescent Proteins