title: Localized Mechanical Stress Promotes Microtubule Rescue.
abstract: Microtubule dynamics rely on the properties of tubulin and are regulated by microtubule-associated proteins. GTP-tubulin assembles into hollow polymers, which can depolymerize upon GTP hydrolysis. Depolymerizing microtubules may stop shrinking and resume growth. Such rescues are regulated by microtubule-associated proteins like CLIP-170 and the CLASPs [1, 2]. Microtubule domains prone to rescues contain discrete regions (previously termed "GTP islands") that retain a GTP-tubulin-like conformation in the main body of the microtubule [3]. However, the exact nature of these domains and the mechanisms controlling their occurrence and distribution are largely unknown. Here we show that collisions between growing microtubules and mechanical obstacles (including other microtubules) in vitro result in the higher abundance of GTP-like islands in stressed microtubule regions. Furthermore, these islands were found to be efficiently generated by both lateral contacts and mechanical constraints applied to the main body of the microtubules. They were also particularly prominent where shifts in the number of protofilaments occur in the microtubule lattice. GTP-like islands and rescues frequently co-occurred at microtubule intersections in vitro and in living cells, both in crossing and in crossed microtubules. We also observed that CLIP-170 recognizes GTP-like islands in vivo and is retained at microtubule crossings. Therefore, we propose that rescues occur via a two-stage mechanism: (1) lattice defects determine potential rescue-promoting islands in the microtubule structure, and (2) CLIP-170 detects these islands to stimulate microtubule rescue. Our results reveal the interplay between rescue-promoting factors and microtubule architecture and organization to control microtubule dynamics.
authors.affiliation: Institut Curie, PSL Research University, CNRS UMR 144, rue d'Ulm, 75246 Paris Cedex 05, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: de Forges
authors.affiliation: INSERM UMR-S 1193, Univ. Paris-Sud, Université Paris-Saclay, rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France; Biochimie, APHP, Hôpitaux Universitaires de l'Est Parisien, Site St Antoine, rue du Faubourg Saint Antoine, 75571 Paris Cedex 12, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Pilon
authors.affiliation: INSERM UMR-S 1193, Univ. Paris-Sud, Université Paris-Saclay, rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Cantaloube
authors.affiliation: CNRS UPR 20, Laboratoire de Photonique et Nanostructures, route de Nozay, F-91460 Marcoussis, France; Univ. Paris-Sud, Université Paris-Saclay, Faculté de Pharmacie, rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Pallandre
authors.affiliation: CNRS UPR 20, Laboratoire de Photonique et Nanostructures, route de Nozay, F-91460 Marcoussis, France.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Haghiri-Gosnet
authors.affiliation: Institut Curie, PSL Research University, CNRS UMR 144, rue d'Ulm, 75246 Paris Cedex 05, France. Electronic address: franck.perez@curie.fr.
authors.forename: Franck
authors.initials: F
authors.lastname: Perez
authors.affiliation: INSERM UMR-S 1193, Univ. Paris-Sud, Université Paris-Saclay, rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France; Biochimie-Hormonologie, APHP, Hôpitaux Universitaires Paris-Sud, Site Antoine Béclère, rue de la Porte de Trivaux, 92141 Clamart, France. Electronic address: christian.pous@u-psud.fr.
authors.forename: Christian
authors.initials: C
authors.lastname: Poüs
mesh_terms: D000818:Animals; D002460:Cell Line; D006160:Guanosine Triphosphate; D008870:Microtubules / Q000502:physiology*; D056004:Molecular Dynamics Simulation; D011108:Polymers; D011487:Protein Conformation
chemical_list: D011108:Polymers; D006160:Guanosine Triphosphate
keywords: CLIP-170; GTP islands; cytoskeleton; mechanical stress; microtubule crossings; microtubule dynamics; microtubule rescue