The Correct Localization of Borealin in Midbody during Cytokinesis Depends on IQGAP1.

Reziya Wumaier,Hexige Saiyin,Lihuan Cao,Abudunaibi Aili,Aikeremujiang Muheremu,Pingzhao Zhang

doi:10.1155/2020/6231697

Abstract

Borealin is a key component of chromosomal passenger complex, which is vital in cytokinesis. IQ domain-containing GTPase-activating protein 1 (IQGAP1) also participates in cytokinesis. The correlation between Borealin and IQGAP1 during cytokinesis is not yet clear. Here, we used mass spectrometry and endogenous coimmunoprecipitation experiments to investigate the interaction between IQGAP1 and Borealin. Results of the current study showed that Borealin interacted directly with IQGAP1 both in vitro and in vivo. Knockdown of IQGAP1 resulted in an abnormal location of Borealin in the midbody. Knocking down Borealin alone, IQGAP1 alone, or Borealin and IQGAP1 at the same time inhibited the completion of cytokinesis and formed multinucleated cells. Our results indicated that IQGAP1 interacts with Borealin during cytokinesis, and the correct localization of Borealin in the midbody during cytokinesis is determined by IQGAP1, and IQGAP1 may play an important role in regulating Borealin function in cytokinesis.

Highlights

Cytokinesis controls the proper distribution of the replicated cytoplasm and nuclear material in two daughter cells
The HeLa monoclonal cell line was constructed with stably expressing Flag-HA-tagged Borealin protein, after treatment with double-thymidine block (DTB); cells whose division process synchronized to cytokinesis were collected
We identified IQ domain-containing GTPaseactivating protein 1 (IQGAP1) as one of the Borealininteracting proteins, and its score was comparable to or higher than the other members of chromosomal passenger complex (CPC), survivin, INCENP, and Aurora B (Table 1)

Summary

Introduction

Cytokinesis controls the proper distribution of the replicated cytoplasm and nuclear material in two daughter cells. If this process is abnormal or defective, it will lead to the failure of previous mitotic events and cause cell polyploidy and chromosome instability [1]. The midbody provides an important platform for recruiting and organizing crucial proteins that regulate the detachment of two daughter cells [3]. These midbody proteins can be divided into three subgroups according to their positions: the bulge, the dark zone, and the flanking zone proteins [4]

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Conclusion