Spatial Localization of Mono-and Diphosphorylated Myosin II Regulatory Light Chain at the Leading Edge of Motile HeLa Cells

Cell Structure and Function

Hiroshi Hosoya¹  Katsumi Fumoto¹  Yoshihiro Yamamoto¹  Kozue Ueda¹  Takashi Uchimura¹ 

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

关键词: myosin II regulatory light chain;    phosphorylation;    subcellular localization;    confocal laser microscopy;    wound healing;    leading edge;   

DOI  :  10.1247/csf.27.479

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(26)Cited-By(15)Nonmuscle myosin II activity is regulated by phosphorylation of the myosin II regulatory light chain (MRLC) at Ser19 or at both Thr18 and Ser19, and the phosphorylation of MRLC promotes the contractility and stability of actomyosin. To analyze the states of MRLC phosphorylation at the leading edge in the motile HeLa cells, we have examined the subcellular distribution of monophosphorylated or diphosphorylated form of MRLC using a confocal microscope. The cross-sectional imaging revealed that monophosphorylated MRLC distributed throughout the cortical region and the leading edge, but its fluorescent signal was much stronger at the leading edge. This distribution pattern of monophosphorylated MRLC was almost identical to those of myosin II and F-actin. On the other hand, diphosphorylated MRLC is localized at the base of leading edge, spatially very close to the substrate, and colocalized with F-actin in part at the base of filopodia. Diphosphorylated MRLC was hardly detectable at the tip of filopodia and the cell cortical region, where monophosphorylated MRLC was clearly detected. These localization patterns suggest that myosin II is activated at the leading edge, especially at the base but not the tip of filopodia in motile cells. Next, we analyzed the cells expressing GFP-tagged recombinant MRLCs. Expression of GFP-tagged diphosphorylatable and monophosphorylatable MRLCs led to a significant increase in the filopodial number, compared with the cells expressing nonphosphorylatable MRLC. This result indicated that expression of phosphorylatable MRLC enhances the formation of filopodia at the wound edge.

【 授权许可】

Unknown