How to scaffold the contractile ring for a safe cytokinesis – lessons from Anillin-related proteins

Pier Paolo D'Avino

doi:10.1242/jcs.034785

Abstract

The ingression of a cleavage furrow separates the two daughter cells at the end of cell division. In many organisms this furrow ingression is driven by the assembly and contraction of actomyosin filaments, forming a contractile ring. To achieve a successful cytokinesis, these actomyosin filaments need to be assembled in an organized manner. For this purpose, a network of cytoskeletal proteins is built at the cleavage site to act as a scaffold for actomyosin filaments and to connect them to the plasma membrane. The Drosophila melanogaster protein Anillin, and its related proteins in other organisms, has a pivotal role in the organization of this scaffold in many species, ranging from yeast to humans. Recent studies indicate that Anillin-related proteins interact not only with the structural components of the contractile ring, but also with the signalling factors that control their dynamics. In addition, Drosophila Anillin connects the actomyosin ring to the spindle microtubules through its interaction with the RacGAP component of the centralspindlin complex. Here I review the structures and functions of Anillin and Anillin-related proteins in various model systems, and aim to highlight both the common and distinctive features of these essential organizers of the molecular machinery that drives furrow ingression.

Highlights

During cytokinesis, which occurs at the end of cell division, a cleavage furrow forms between the segregating chromosomes and ingresses to bisect the dividing cell (D’Avino et al, 2005; Eggert et al, 2006)
The mechanisms that are responsible for furrow positioning vary considerably from yeast to metazoans (Balasubramanian et al, 2004; Barr and Gruneberg, 2007; Guertin et al, 2002), current models propose that furrow ingression is always driven by the assembly and contraction of actomyosin filaments that organize into a contractile ring (Fig. 1A), a very dynamic structure in which filaments are continuously assembled and disassembled
C-terminal Anillin homology region (AHR) with a PH domain, but only ANI-1 contains sequences towards the N-terminus that are similar to the myosinand actin-binding domains that are observed in humans and vertebrates (Fig. 2) (Maddox et al, 2005)

Summary

Introduction

During cytokinesis, which occurs at the end of cell division, a cleavage furrow forms between the segregating chromosomes and ingresses to bisect the dividing cell (D’Avino et al, 2005; Eggert et al, 2006). The signalling pathways that control assembly and contraction of the ring differ considerably among organisms These mechanisms and pathways have been recently reviewed in detail (Balasubramanian et al, 2004; Barr and Gruneberg, 2007; D’Avino et al, 2005; Eggert et al, 2006) and are beyond the scope of this article. Of Pbl/ECT2 requires it to interact with the Rho-family GTPaseactivating protein (GAP) known as RacGAP50C in Drosophila and MgcRacGAP in mammals (Fig. 1B) (Kamijo et al, 2006; Nishimura and Yonemura, 2006; Somers and Saint, 2003; Yuce et al, 2005; Zhao and Fang, 2005b).

Myosin activity

Basic region

Cleavage furrow Telophase

Actomyosin filaments

Conclusions and future perspectives