Actomyosin Ring Formation and Tension Generation in Eukaryotic Cytokinesis

Abstract

Cell division facilitated by a contractile ring is an almost universal feature across all branches of cellular life, with the notable exception of higher plants. In all organisms that use a contractile ring for cell division, the process of cytokinesis can be divided into four distinct stages. Firstly, the cell needs to specify a location at which to place the cell division ring to ensure proper separation of the cell contents into two daughter cells. Secondly, the cell needs to be able to transport all the necessary components to this region, and construct the cell division ring reliably and efficiently. Thirdly, the cell division ring needs to generate contractile stress in a regulated manner, to physically cleave the mother cell into two daughter cells. Finally, the ring must be disassembled to allow for the final abscission and separation of the daughter cells. In this review, we will discuss some of the proposed mechanisms by which eukaryotic cells are able to complete the first three of these stages. While there is a good understanding of the mechanisms of division site specification in most organisms, and the mechanisms of actomyosin ring formation are well studied in fission and budding yeast, there is relatively poor understanding of how actomyosin interactions are able to generate contractile stresses during ring constriction, although a number of models have been proposed. We also discuss a number of myosin motor-independent mechanisms that have been proposed to generate contractile stress in various organisms.

Myosin IIA-related Actomyosin Contractility Mediates Oxidative Stress-induced Neuronal Apoptosis

“…We also showed for the first time that PC12 cells with myosin IIB knockdown had a higher proliferative activity than myosin IIA knockdown or control cells. It has been reported that cytokinesis is facilitated by the constriction of a cortical ring made up of myosin II and actin filaments in animal and fungal cells (Cheffings et al, 2016; Zambon et al, 2017). Actomyosin-drived cellular contractility is recognized as an important promoter for increased tumor number, growth and progression (Samuel et al, 2011).…”

Myosin-independent cytokinesis in Giardia utilizes flagella to coordinate force generation and direct membrane trafficking

“…The ability to follow fluorescent proteins in live cells has been one of the most powerful tools for uncovering the mechanism of cytokinesis in model systems (34). To study the dynamics of individual proteins during the cell cycle, we developed a low-fluorescence culture medium that supports cell growth.…”

Motor Activity Dependent and Independent Functions of Myosin II Contribute to Actomyosin Ring Assembly and Contraction in Schizosaccharomyces pombe

“…SummaryCytokinesis depends on a contractile actomyosin ring in many eukaryotes [1, 2, 3]. Myosin II is a key component of the actomyosin ring, although whether it functions as a motor or as an actin cross-linker to exert its essential role is disputed [1, 4, 5].…”