Sumoylation of Kif18A plays a role in regulating mitotic progressionReport as inadecuate

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BMC Cancer

, 15:197

Cell and molecular biology


BackgroundKif18A, the kinesin-8 motor protein, plays an essential role in regulating alignment of bi-oriented chromosomes at the midzone during mitosis. Kinesin proteins, including Kif18A, are often deregulated in many types of cancers and are thought to play a critical role in cancer progression. However, little is known about the post-translational modifications of Kif18A and their effects on its biological activity.

MethodsKif18A was identified to be a SUMO2 acceptor by using Ni-IDA resin to precipitate proteins from cells stably expressing His6-SUMO2. To identify the potential lysine residues, multi-site directed mutagenesis together with transient transfection and Ni-IDA pull-down assay were carried out. The confocal time-lapse imaging and immunofluorescent staining were used to study the roles of SUMO2 modification on Kif18A’s activity during the cell cycle.

ResultsKif18A is covalently modified by SUMO2 during the cell cycle, and its sumoylation peaks at metaphase and then rapidly decreases upon anaphase onset. Mutational analysis identifies multiple lysine residues K148, K442, K533, K660 and K683 as potential SUMO acceptors. The functional studies reveal that sumoylation of Kif18A has little effect on protein stability and subcellular localization. However, compared with the wild-type control, ectopic expression of SUMO-resistant mutants of Kif18A results in a significant delay of mitotic exit. Confocal microscopy shows that cells expressing SUMO-resistant Kif18A display a compromised dissociation of BubR1 from kinetochores after anaphase onset.

ConclusionsOur studies reveal that sumoylation functions as an unidentified form of post-translational modification that regulates Kif18A activity during mitotic progression.

KeywordsKif18A Sumoylation Cell cycle Mitosis Motor protein Microtubules Electronic supplementary materialThe online version of this article doi:10.1186-s12885-015-1226-9 contains supplementary material, which is available to authorized users.

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Author: Feikun Yang - Yan Chen - Wei Dai


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