Human ECT2 is an exchange factor for Rho GTPases, phosphorylated in G2/M phases, and involved in cytokinesis

Takashi Tatsumoto, Xiaozhen Xie, Rayah Blumenthal, Isamu Okamoto, Toru Miki

Research output: Contribution to journalArticle

308 Citations (Scopus)

Abstract

Animal cells divide into two daughter cells by the formation of an actomyosin-based contractile ring through a process called cytokinesis. Although many of the structural elements of cytokinesis have been identified, little is known about the signaling pathways and molecular mechanisms underlying this process. Here we show that the human ECT2 is involved in the regulation of cytokinesis. ECT2 catalyzes guanine nucleotide exchange on the small GTPases, RhoA, Rac1, and Cdc42. ECT2 is phosphorylated during G2 and M phases, and phosphorylation is required for its exchange activity. Unlike other known guanine nucleotide exchange factors for Rho GTPases, ECT2 exhibits nuclear localization in interphase, spreads throughout the cytoplasm in prometaphase, and is condensed in the midbody during cytokinesis. Expression of an ECT2 derivative, containing the NH2-terminal domain required for the midbody localization but lacking the COOH-terminal catalytic domain, strongly inhibits cytokinesis. Moreover, microinjection of affinity- purified anti-ECT2 antibody into interphase cells also inhibits cytokinesis. These results suggest that ECT2 is an important link between the cell cycle machinery and Rho signaling pathways involved in the regulation of cell division.

Original languageEnglish
Pages (from-to)921-927
Number of pages7
JournalJournal of Cell Biology
Volume147
Issue number5
DOIs
Publication statusPublished - Nov 29 1999
Externally publishedYes

    Fingerprint

All Science Journal Classification (ASJC) codes

  • Cell Biology

Cite this