Determinants of Myosin II Cortical Localization during Cytokinesis

TY - JOUR

T1 - Determinants of Myosin II Cortical Localization during Cytokinesis

A1 - Uehara,Ryota

A1 - Goshima,Gohta

A1 - Mabuchi,Issei

A1 - Vale,Ronald D.

A1 - Spudich,James A.

A1 - Griffis,Eric R.

AU - Uehara,Ryota

AU - Goshima,Gohta

AU - Mabuchi,Issei

AU - Vale,Ronald D.

AU - Spudich,James A.

AU - Griffis,Eric R.

PY - 2010/6/22

Y1 - 2010/6/22

N2 - <p>Myosin II is an essential component of the contractile ring that divides the cell during cytokinesis. Previous work showed that regulatory light chain (RLC) phosphorylation is required for localization of myosin at the cellular equator [1, 2]. However, the molecular mechanisms that concentrate myosin at the site of furrow formation remain unclear. By analyzing the spatiotemporal dynamics of mutant myosin subunits in Drosophila S2 cells, we show that myosin accumulates at the equator through stabilization of interactions between the cortex and myosin filaments and that the motor domain is dispensable for localization. Filament stabilization is tightly controlled by RLC phosphorylation. However, we show that regulatory mechanisms other than RLC phosphorylation contribute to myosin accumulation at three different stages: (1) turnover of thick filaments throughout the cell cycle, (2) myosin heavy chain-based control of myosin assembly at the metaphase-anaphase transition, and (3) redistribution and/or activation of myosin binding sites at the equator during anaphase. Surprisingly, the third event can occur to a degree in a Rho-independent fashion, gathering preassembled filaments to the equatorial zone via cortical flow. We conclude that multiple regulatory pathways cooperate to control myosin localization during mitosis and cytokinesis to ensure that this essential biological process is as robust as possible.</p>

AB - <p>Myosin II is an essential component of the contractile ring that divides the cell during cytokinesis. Previous work showed that regulatory light chain (RLC) phosphorylation is required for localization of myosin at the cellular equator [1, 2]. However, the molecular mechanisms that concentrate myosin at the site of furrow formation remain unclear. By analyzing the spatiotemporal dynamics of mutant myosin subunits in Drosophila S2 cells, we show that myosin accumulates at the equator through stabilization of interactions between the cortex and myosin filaments and that the motor domain is dispensable for localization. Filament stabilization is tightly controlled by RLC phosphorylation. However, we show that regulatory mechanisms other than RLC phosphorylation contribute to myosin accumulation at three different stages: (1) turnover of thick filaments throughout the cell cycle, (2) myosin heavy chain-based control of myosin assembly at the metaphase-anaphase transition, and (3) redistribution and/or activation of myosin binding sites at the equator during anaphase. Surprisingly, the third event can occur to a degree in a Rho-independent fashion, gathering preassembled filaments to the equatorial zone via cortical flow. We conclude that multiple regulatory pathways cooperate to control myosin localization during mitosis and cytokinesis to ensure that this essential biological process is as robust as possible.</p>

KW - DROSOPHILA S2 CELLS

KW - NONMUSCLE MYOSIN

KW - CHAIN PHOSPHORYLATION

KW - HEAVY-CHAIN

KW - LIGHT-CHAIN

KW - FILAMENT FORMATION

KW - RECRUITMENT

KW - PROTEIN

KW - KINASE

KW - FURROW

U2 - 10.1016/j.cub.2010.04.058

DO - 10.1016/j.cub.2010.04.058

M1 - Article

JO - Current Biology

JF - Current Biology

SN - 0960-9822

IS - 12

VL - 20

SP - 1080

EP - 1085

ER -