Distinct Roles of Myosin-II Isoforms in Cytokinesis under Normal and Stressed Conditions

Summary

To address the question of why more than one myosin-II isoform is expressed in a single cell to drive cytokinesis, we analyzed the roles of the myosin-II isoforms, Myo2 and Myp2, of the fission yeast Schizosaccharomyces pombe, in cytokinesis under normal and stressed conditions. We found that Myp2 controls the disassembly, stability, and constriction initiation of the Myo2 ring in response to high-salt stress. A C-terminal coiled-coil domain of Myp2 is required for its immobility and contractility during cytokinesis, and when fused to the tail of the dynamic Myo2, renders the chimera the low-turnover property. We also found, by following distinct processes in real time at the single-cell level, that Myo2 and Myp2 are differentially required but collectively essential for guiding extracellular matrix remodeling during cytokinesis. These results suggest that the dynamic and immobile myosin-II isoforms are evolved to carry out cytokinesis with robustness under different growth conditions.

Graphical Abstract

Highlights

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  The myosin-II isoforms Myo2 and Myp2 display distinct responses to cellular stress

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  Myp2 controls the constriction initiation of Myo2 during stress response

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  A C-terminal region of Myp2 is required for its immobility during cytokinesis

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  Myo2 and Myp2 are differentially required for guiding ECM remodeling during cytokinesis

Abstract

Molecular Mechanism of Behavior; Cell Biology; Functional Aspects of Cell Biology