Kinetochores use a novel mechanism for coordinating the dynamics of individual microtubules

• Type: Article in International Scientific Journal
• Date: 2006

Authors

VandenBeldt, KJ (Author) Other; Barnard, RM (Author) Other; Hergert, PJ (Author) Other; Meng, X (Author) Other; Helder Maiato (Author) FMUP; McEwen, BF (Author) Other

Journal

Title: Current Biology

Vol. 16

Pages: 1217-1223

ISSN: 0960-9822

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 53 Citations

Scopus - 56 Citations

Other information

Authenticus ID: P-004-K4G

DOI: 10.1016/j.cub.2006.04.046

Abstract (EN): Chromosome alignment during mitosis is frequently accompanied by a dynamic switching between elongation and shortening of kinetochore fibers (K-fibers) that connect kinetochores and spindle poles [1, 2]. In higher eukaryotes, mature K-fibers consist of 10-30 kinetochore microtubules (kMTs) whose plus ends are embedded in the kinetochore [1-3]. A critical and long-standing question is how the dynamics of individual kMTs within the K-fiber are coordinated [1-5]. We have addressed this question by using electron tomography to determine the polymerization/depolymerization status of individual kMTs in the K-fibers of PtK1 and Drosophila S2 cells. Surprisingly, we find that the plus ends of two-thirds of kMTs are in a depolymerizing state, even when the K-fiber exhibits net tubulin incorporation at the plus end [6-8]. Furthermore, almost all individual K-fibers examined had a mixture of kMTs in the polymerizing and depolymerizing states. Therefore, although K-fibers elongate and shrink as a unit, the dynamics of individual kMTs within a K-fiber are not coordinated at any given moment. Our results suggest a novel control mechanism through which attachment to the kinetochore outer plate prevents shrinkage of kMTs. We discuss the ramifications of this new model on the regulation of chromosome movement and the stability of K-fibers.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7