RT Journal Article
SR Electronic
T1 Kif2 microtubule depolymerase is required for unequal cell division and localizes to a subdomain of cortical endoplasmic reticulum
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 171041
DO 10.1101/171041
A1 Vlad Costache
A1 Celine Hebras
A1 Gerard Pruliere
A1 Lydia Besnardeau
A1 Margaux Failla
A1 Richard R. Copley
A1 David Burgess
A1 Janet Chenevert
A1 Alex McDougall
YR 2017
UL http://biorxiv.org/content/early/2017/08/01/171041.abstract
AB Unequal cell division (UCD) is a fundamental process responsible for creating sibling cell size asymmetry; however, how microtubules are specifically depolymerized on one aster of the mitotic spindle creating a smaller sibling cell during UCD has remained elusive. Using invertebrate chordate embryos (ascidian) that possess a large cortical structure (CAB) that causes UCD, we identified a microtubule depolymerase (Kif2) involved in creating cell size asymmetry. Kif2 localizes to the cortical subdomain of endoplasmic reticulum in the CAB. During three successive UCDs, Kif2 protein accumulates at the CAB during interphase and is delocalized from the CAB in mid mitosis. Rapid imaging of microtubule dynamics at the cortex revealed that microtubules do not penetrate the CAB during interphase. Inhibition of Kif2 function prevents the development of mitotic aster asymmetry and centrosome movement towards the CAB thereby blocking UCD, whereas locally increasing microtubule depolymerization causes exaggerated asymmetric spindle positioning. This study provides insights into the fundamental process of UCD and for the first time shows that a microtubule depolymerase is localized to a cortical site controlling UCD.