title: Interaction of Skp1 with CENP-E at the midbody is essential for cytokinesis.
abstract: Centromere-associated protein E (CENP-E) is a kinesin-related microtubule motor protein that is essential for chromosome congression during mitosis. Our previous studies show that microtubule motor CENP-E represents a link between attachment of spindle microtubules and the mitotic checkpoint signaling cascade. However, the molecular function of CENP-E at the midbody had remained elusive. Here we show that CENP-E interacts with Skp1 at the midbody and participates in cytokinesis. CENP-E interacts with Skp1 in vitro and in vivo via its coiled-coil domain. Our yeast two-hybrid assays mapped the binding interfaces to the central stalk region of CENP-E (955-1571 aa) and the C-terminal 33 amino acids of Skp1, respectively. Our immunocytochemical studies revealed that CENP-E targets to the midbody prior to Skp1 and the midbody localization of CENP-E becomes diminished as Skp1 arrives at the midbody. Suppression of Skp1 in mitotic HeLa cells by siRNA resulted in accumulation of telophase cells with elongated inter-cell bridges and with midbodies stretched 2-3 times longer than that of normal cells. These Skp1-eliminated or -suppressed cells accumulate higher level of CENP-E, suggesting that spatiotemporal regulation of CENP-E degradation at the midbody is essential for cytokinesis. Over-expression of Skp1 lacking the CENP-E-binding domain confirmed that Skp1-CENP-E interaction is essential for faithful cytokinesis. We hypothesize that CENP-E degradation is essential for faithful mitotic exit and the proteolysis of CENP-E is mediated by SCF via a direct Skp1 link.
authors: Division of Cellular Dynamics, Hefei National Laboratory and University of Science & Technology of China, Hefei, China 230027.
authors: Dan
authors: D
authors: Liu
authors: Ning
authors: N
authors: Zhang
authors: Jian
authors: J
authors: Du
authors: Xin
authors: X
authors: Cai
authors: Mei
authors: M
authors: Zhu
authors: Changjiang
authors: C
authors: Jin
authors: Zhen
authors: Z
authors: Dou
authors: Cijian
authors: C
authors: Feng
authors: Ye
authors: Y
authors: Yang
authors: Li
authors: L
authors: Liu
authors: Kunio
authors: K
authors: Takeyasu
authors: Wei
authors: W
authors: Xie
authors: Xuebiao
authors: X
authors: Yao