Centromere-associated protein-E is essential for the mammalian mitotic checkpoint to prevent aneuploidy due to single chromosome loss

Abstract

Centromere-associated protein-E (CENP-E) is an essential mitotic kinesin that is required for efficient, stable microtubule capture at kinetochores. It also directly binds to BubR1, a kinetochore-associated kinase implicated in the mitotic checkpoint, the major cell cycle control pathway in which unattached kinetochores prevent anaphase onset. Here, we show that single unattached kinetochores depleted of CENP-E cannot block entry into anaphase, resulting in aneuploidy in 25% of divisions in primary mouse fibroblasts in vitro and in 95% of regenerating hepatocytes in vivo. Without CENP-E, diminished levels of BubR1 are recruited to kinetochores and BubR1 kinase activity remains at basal levels. CENP-E binds to and directly stimulates the kinase activity of purified BubR1 in vitro. Thus, CENP-E is required for enhancing recruitment of its binding partner BubR1 to each unattached kinetochore and for stimulating BubR1 kinase activity, implicating it as an essential amplifier of a basal mitotic checkpoint signal.

Functional Analysis of Human Microtubule-based Motor Proteins, the Kinesins and Dyneins, in Mitosis/Cytokinesis Using RNA Interference

“…Consistent with previous studies (Putkey et al, 2002;Weaver et al, 2003;Tanudji et al, 2004), cells depleted of CENP-E exhibit unaligned chromosomes close to spindle poles and misaligned chromosomes positioned between the metaphase plate and spindle poles at metaphase. Kinetochore pairs on misaligned sister chromatids showed no interaction or diminished interaction with spindle MTs.…”

“…Kinetochore pairs on misaligned sister chromatids showed no interaction or diminished interaction with spindle MTs. Previous studies demonstrated that CENP-E binds to kinetochores and MTs and stabilizes their interaction, thereby contributing to silencing the mitotic spindle checkpoint (Putkey et al, 2002;Weaver et al, 2003;Tanudji et al, 2004). CENP-E associates with and activates the mitotic checkpoint kinase BubR1, indicating that the spindle checkpoint is sensed through CENP-E kinetochore activity (Chan et al, 1998(Chan et al, , 1999Mao et al, 2003;Weaver et al, 2003).…”

“…Previous studies demonstrated that CENP-E binds to kinetochores and MTs and stabilizes their interaction, thereby contributing to silencing the mitotic spindle checkpoint (Putkey et al, 2002;Weaver et al, 2003;Tanudji et al, 2004). CENP-E associates with and activates the mitotic checkpoint kinase BubR1, indicating that the spindle checkpoint is sensed through CENP-E kinetochore activity (Chan et al, 1998(Chan et al, , 1999Mao et al, 2003;Weaver et al, 2003). However, the observation that there are few unaligned and/or misaligned chromosomes in CENP-E esiRNAtreated cells suggests that functionally redundant mechanisms may operate to control spindle MT-kinetochore attachment and chromosome congression (Tanudji et al, 2004).…”

SAC‐ing mitotic errors: How the spindle assembly checkpoint (SAC) plays defense against chromosome mis‐segregation

“…However, BubR1 contains a carboxy terminal kinase domain that is absent in yeast Mad3p . BubR1 kinase activity is stimulated by binding to CENP-E Weaver et al, 2003], a kinetochore-associated microtubule motor [Wood et al, 1997] that functions in the SAC in Xenopus and mammalian cells Weaver et al, 2003]. Originally, BubR1 kinase activity was thought to be dispensable for SAC function in Xenopus egg extracts [Chen, 2002;Tang et al, 2001], but a recent study indicates that cells require a threshold level of CENP-E activated BubR1 kinase activity for SAC function and Mad2p recruitment to kinetochores .…”

The role of kinesin family proteins in tumorigenesis and progression

“…68,69 Loss of CENP-E expression or altered function of CENP-E leads to inhibition of chromosome alignment during mitosis, resulting in the initiation of checkpoint activation and a delay in the completion of cell mitosis. 70,71 The inhibition of CENP-E using a potent and selective CENP-E inhibitor GSK923295A reportedly delayed the duration of cell mitosis, as characterized by the presence of lagging, nonequatorially aligned chromosomes associated with the spindle pole, and this was followed by apoptosis. 72,73 Several investigators have reported the efficacy of GSK923295A in nude mouse xenografts, 74 and its antitumor effects are the subject of current phase 1 clinical trials in patients with advanced solid tumors.…”