Directionality of individual kinesin-5 Cin8 motors is modulated by loop 8, ionic strength and microtubule geometry.

Published

Journal Article

Kinesin-5 motors fulfil essential roles in mitotic spindle morphogenesis and dynamics as slow, processive microtubule (MT) plus-end directed motors. The Saccharomyces cerevisiae kinesin-5 Cin8 was found, surprisingly, to switch directionality. Here, we have examined directionality using single-molecule fluorescence motility assays and live-cell microscopy. On spindles, Cin8 motors mostly moved slowly (∼25 nm/s) towards the midzone, but occasionally also faster (∼55 nm/s) towards the spindle poles. In vitro, individual Cin8 motors could be switched by ionic conditions from rapid (380 nm/s) and processive minus-end to slow plus-end motion on single MTs. At high ionic strength, Cin8 motors rapidly alternated directionalities between antiparallel MTs, while driving steady plus-end relative sliding. Between parallel MTs, plus-end motion was only occasionally observed. Deletion of the uniquely large insert in loop 8 of Cin8 induced bias towards minus-end motility and affected the ionic strength-dependent directional switching of Cin8 in vitro. The deletion mutant cells exhibited reduced midzone-directed motility and efficiency to support spindle elongation, indicating the importance of directionality control for the anaphase function of Cin8.

Full Text

Duke Authors

Cited Authors

  • Gerson-Gurwitz, A; Thiede, C; Movshovich, N; Fridman, V; Podolskaya, M; Danieli, T; Lakämper, S; Klopfenstein, DR; Schmidt, CF; Gheber, L

Published Date

  • November 18, 2011

Published In

Volume / Issue

  • 30 / 24

Start / End Page

  • 4942 - 4954

PubMed ID

  • 22101328

Pubmed Central ID

  • 22101328

Electronic International Standard Serial Number (EISSN)

  • 1460-2075

International Standard Serial Number (ISSN)

  • 0261-4189

Digital Object Identifier (DOI)

  • 10.1038/emboj.2011.403

Language

  • eng