Dresden 2017 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 43: Cytoskeletal Filaments
BP 43.6: Vortrag
Mittwoch, 22. März 2017, 16:45–17:00, HÜL 386
Overlapping microtubules establish a microenvironment enabling the autoregulation of molecular motors — •Marcus Braun1,2, Zdenek Lansky1,2,3, Agata Szuba1,2, Friedrich W Schwarz2, Anniruddha Mitra1,2, Mengfei Gao1,2, Annemarie Lüdecke1,2, Pieter Rein ten Wolde4, and Stefan Diez1,2 — 1B CUBE, TU Dresden, Arnoldstraße 18, 01307 Dresden, Germany — 2MPI-CBG, Pfotenhauerstraße 108, 01307 Dresden, Germany — 3CAS, BIOCEV, Prumyslova 595, Vestec 25250, Czech Republic — 4AMOLF, Science Park 104, 1098 XG Amsterdam, the Netherlands
Collective action of molecular motors is required for the remodeling of microtubule networks underpinning essential cellular processes, such as cell division. Among these motors are microtubule-crosslinking motors, which slide microtubules along each other. However, additional regulatory proteins are thought to be necessary to establish stable overlaps between the sliding microtubules and to prevent the breakdown of the networks. Here, we show in vitro that human kinesin-14 HSET motors - as they slide overlapping microtubules apart - collectively detect the decrease in overlap length and slow down the sliding in an autoregulatory manner, leading to the formation of stable overlaps. Slowdown is quantitatively explained by the dependence of HSET sliding on the local HSET density in the overlap and the generation of an entropic force antagonizing the sliding. We argue that overlapping filaments, when crosslinked by proteins sensitive to their spatial arrangement, establish envelope-free compartments constituting distinct microenvironments that can locally catalyze biochemical processes.