Polo kinase recruitment via the constitutive centromere-associated network at the kinetochore elevates centromeric RNA

The kinetochore, a multi-protein complex assembled on centromeres, is essential to segregate chromosomes during cell division. Deficiencies in kinetochore function can lead to chromosomal instability and aneuploidy-a hallmark of cancer cells. Kinetochore function is controlled by recruitment of regulatory proteins, many of which have been documented, however their function often remains uncharacterized and many are yet to be identified. To identify candidates of kinetochore regulation we used a proteome-wide protein association strategy in budding yeast and detected many proteins that are involved in post-translational modifications such as kinases, phosphatases and histone modifiers. We focused on the Polo-like kinase, Cdc5, and interrogated which cellular components were sensitive to constitutive Cdc5 localization. The kinetochore is particularly sensitive to constitutive Cdc5 kinase activity. Targeting Cdc5 to different kinetochore subcomplexes produced diverse phenotypes, consistent with multiple distinct functions at the kinetochore. We show that targeting Cdc5 to the inner kinetochore, the constitutive centromere-associated network (CCAN), increases the levels of centromeric RNA via an SPT4 dependent mechanism

Programas sociales, pobreza y participación ciudadana

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Programas sociales, pobreza y participación ciudadana

Esta publicación tiene por objeto establecer, empíricamente, la complementariedad entre el Estado y la sociedad civil en el marco de las políticas sociales y la lucha contra la pobreza

Cnn1 inhibits the interactions between the KMN complexes of the yeast kinetochore

El pdf del artículo es la versión de autor.-- et al.Kinetochores attach the replicated chromosomes to the mitotic spindle and orchestrate their transmission to the daughter cells. Kinetochore-spindle binding and chromosome segregation are mediated by the multi-copy KNL1 Spc105, MIS12 Mtw1 and NDC80 Ndc80 complexes that form the so-called KMN network. KMN-spindle attachment is regulated by the AuroraB Ipl1 and MPS1 Mps1 kinases. It is unclear whether other mechanisms exist that support KMN activity during the cell cycle. Using budding yeast, we show that kinetochore protein Cnn1 localizes to the base of the Ndc80 complex and promotes a functionally competent configuration of the KMN network. Cnn1 regulates KMN activity in a spatiotemporal manner by inhibiting the interaction between its complexes. Cnn1 activity peaks in anaphase and is driven by the Cdc28, Mps1 and Ipl1 kinases. © 2012 Macmillan Publishers Limited. All rights reserved.P.D.W. acknowledges financial support from the Italian Association for Cancer Research (grant 8840). T.R.H. recognizes support from the N.I.H. (grant GM087461) and the American Cancer Society (grant IRG 58-006-50). T.U.T. acknowledges a Cancer Research U.K. senior fellowship and Wellcome Trust program grant. L.J.B. acknowledges a doctoral fellowship from the European School of Molecular Medicine.Peer Reviewe