Successive Kinesin-5 Microtubule Crosslinking and Sliding Promote Fast, Irreversible Formation of a Stereotyped Bipolar Spindle.
Curr Biol
; 29(22): 3825-3837.e3, 2019 11 18.
Article
in En
| MEDLINE
| ID: mdl-31679937
ABSTRACT
Separation of duplicated spindle poles is the first step in forming the mitotic spindle. Kinesin-5 crosslinks and slides anti-parallel microtubules (MTs), but it is unclear how these two activities contribute to the first steps in spindle formation. In this study, we report that in monopolar spindles, the duplicated spindle poles snap apart in a fast and irreversible step that produces a nascent bipolar spindle. Using mutations in Kinesin-5 that inhibit microtubule sliding, we show that the fast, irreversible pole separation is primarily driven by microtubule crosslinking. Electron tomography revealed microtubule pairs in monopolar spindles have short overlaps that intersect at high angles and are unsuited for ensemble Kinesin-5 sliding. However, maximal extension of a subset of anti-parallel microtubule pairs approaches the length of nascent bipolar spindles and is consistent with a Kinesin-5 crosslinking-driven transition. Nonetheless, microtubule sliding by Kinesin-5 contributes to stabilizing the nascent spindle and setting its stereotyped equilibrium length.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Kinesins
/
Spindle Apparatus
Language:
En
Journal:
Curr Biol
Journal subject:
BIOLOGIA
Year:
2019
Type:
Article
Affiliation country:
Canada