TY - JOUR
T1 - Directionality of individual kinesin-5 Cin8 motors is modulated by loop 8, ionic strength and microtubule geometry
AU - Gerson-Gurwitz, Adina
AU - Thiede, Christina
AU - Movshovich, Natalia
AU - Fridman, Vladimir
AU - Podolskaya, Maria
AU - Danieli, Tsafi
AU - Lakämper, Stefan
AU - Klopfenstein, Dieter R.
AU - Schmidt, Christoph F.
AU - Gheber, Larisa
PY - 2011/12/14
Y1 - 2011/12/14
N2 - 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.
AB - 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.
KW - Cin8
KW - kinesin directionality
KW - kinesin-5
KW - microtubules
KW - mitosis
UR - http://www.scopus.com/inward/record.url?scp=83555164602&partnerID=8YFLogxK
U2 - 10.1038/emboj.2011.403
DO - 10.1038/emboj.2011.403
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C2 - 22101328
AN - SCOPUS:83555164602
SN - 0261-4189
VL - 30
SP - 4942
EP - 4954
JO - EMBO Journal
JF - EMBO Journal
IS - 24
ER -