Motor-Independent Targeting of CLASPs to Kinetochores by CENP-E Promotes Microt...

• Autor(es): Maffin, Stefano ; Maia, Ana R. R. ; Manning, Amity L. ; Maliga, Zoltan ; Pereira, Ana L. ; Junqueira, Magno ; Shevchenko, Andrej ; Hyman, Anthony ; Yates, John R. ; Galjart, Niels ; Compton, Duane A. ; Maiato, Helder
• Data: 2009
• Identificador Persistente: http://hdl.handle.net/10216/53558
• Origem: Repositório Aberto da Universidade do Porto
• Assunto(s): Flux; Kinetochore; Microtubule turnover; Mitosis; Mitotic spindle
• Tipo de Documento: Artigo
• Idioma: Inglês

Descrição

Efficient chromosome segregation during mitosis relies on the coordinated activity of molecular motors with proteins that regulate kinetochore attachments to dynamic spindle microtubules [1]. CLASPs are conserved kinetochore- and microtubule-associated proteins encoded by two paralogue genes, clasp1 and clasp2, and have been previously implicated in the regulation of kinetochore-microtubule dynamics [2-4]. However, it remains unknown how CLASPs work in concert with other proteins to form a functional kinetochore-microtubule interface. Here we have identified mitotic interactors of human CLASP1 using a proteomic approach. Among these, the microtubule plus-end directed motor CENP-E [5] was found to form a complex with CLASP1 that co-localizes to multiple structures of the mitotic apparatus in human cells. We found that CENP-E recruits both CLASP1 and CLASP2 to kinetochores independent of its motor activity or the presence of microtubules. Depletion of CLASPs or CENP-E by RNAi in human cells causes a significant and comparable reduction of kinetochore-microtubule poleward flux and turnover rates, as well as rescues spindle bipolarity in Kif2a-depleted cells. We conclude that CENP-E integrates two critical functions that are important for accurate chromosome movement and spindle architecture: one relying directly on its motor activity and the other involving the targeting of key microtubule regulators to kinetochores.