Centromere protein (CENP)-W interacts with heterogeneous nuclear ribonucleoprotein (hnRNP) U and may contribute to kinetochore-microtubule attachment in mitotic cells

Abstract

Background: Recent studies have shown that heterogeneous nuclear ribonucleoprotein U (hnRNP U), a component of the hnRNP complex, contributes to stabilize the kinetochore-microtubule interaction during mitosis. CENP-W was identified as an inner centromere component that plays crucial roles in the formation of a functional kinetochore complex. Results: We report that hnRNP U interacts with CENP-W, and the interaction between hnRNP U and CENP-W mutually increased each other's protein stability by inhibiting the proteasomemediated degradation. Further, their co-localization was observed chiefly in the nuclear matrix region and at the microtubule-kinetochore interface during interphase and mitosis, respectively. Both microtubule-stabilizing and microtubule-destabilizing agents significantly decreased the protein stability of CENP-W. Furthermore, loss of microtubules and defects in microtubule organization were observed in CENP-W-depleted cells. Conclusion: Our data imply that CENP-W plays an important role in the attachment and interaction between microtubules and kinetochore during mitosis.