Diphosphorylated MRLC is Required for Organization of Stress Fibers in Interphase Cells and the Contractile Ring in Dividing Cells

Cell Structure and Function

Hiroshi Hosoya¹  Shu Ishitobi¹  Maki Murata-Hori¹  Takahiro Iwasaki¹ 

[1] Department of Biological Science, Graduate School of Science, Hiroshima University

关键词: phosphorylation;    myosin II filament;    myosin II regulatory light chain;    cytokinesis;   

DOI  :  10.1247/csf.26.677

学科分类：分子生物学，细胞生物学和基因

来源: Japan Society for Cell Biology

【 摘 要 】

References(25)Cited-By(39)Activity of nonmuscle myosin II is regulated by phosphorylation of its regulatory light chain (MRLC). Phosphoryration of MRLC at both Thr18 and Ser19 (diphosphorylation) results in higher MgATPase activity and in promotion of the assembly of myosin II filaments than does that of MRLC at Ser19 (monophosphorylation) in vitro. To determine the roles of the diphosphorylated MRLC in vivo, we transfected three kinds of MRLC mutants, unphosphorylated, monophosphorylated and diphosphorylated forms (MRLC2T18AS19A, substitution of both Ser19 and Thr18 by Ala; MRLC2T18AS19D, Ser19 by Asp and Thr18 by Ala; and MRLC2T18DS19D, both Ser19 and Thr18 by Asp, respectively), into HeLa cells. Cells overexpressing the mutant MRLC2T18DS19D contained a larger number of actin filament bundles than did those overexpressing the mutant MRLC2 T18AS19D. Moreover, cells overexpressing the nonphosphorylatable mutant MRLC2T18AS19A showed a decrease in the number of actin filament bundles. Taken together, our data suggest that diphosphorylation of MRLC plays an important role in regulating actin filament assembly and reorganization in nonmuscle cells.

【 授权许可】

Unknown