PAK1 regulates myosin II-B phosphorylation, filament assembly, localization and cell chemotaxis

Liron Even-Faitelson, Michael Rosenberg, Shoshana Ravid*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


Serine/threonine p21-activated kinase is an effector of Rac with a key role in the regulation of cytoskeletal organization. Non-muscle myosin II is a molecular motor, which is an important component of the cytoskeleton. Non-muscle myosin II-B plays a major role in cell motility and chemotaxis. We investigated the role of Rac and p21-activated kinase 1 (PAK1) in the regulation of myosin II-B in prostate cancer cells in response to epidermal growth factor (EGF) stimulation. We found that both Rac and PAK1 affect EGF-dependent non-muscle heavy chain II-B localization and cell morphology. We further found that a dominant negative mutant of PAK1 significantly inhibits EGF-dependent myosin II-B heavy chains phosphorylation and filament disassembly. Furthermore, cells expressing the dominant negative mutant exhibited an increase in EGF-dependent myosin light chain phosphorylation and diminished chemotaxis towards EGF. To our knowledge this is the first report exploring the role of PAK1 in the regulation of both non-muscle myosin II-B heavy chains and light chains. Furthermore, the data presented here suggest that PAK1 plays a crucial role in the regulation of cell morphology and chemotaxis by regulating the phosphorylation and cellular localization of myosin II-B.

Original languageAmerican English
Pages (from-to)1137-1148
Number of pages12
JournalCellular Signalling
Issue number9
StatePublished - Sep 2005

Bibliographical note

Funding Information:
This work was supported by grants from the Israel Cancer Research Foundation, the Israeli Ministry of Health and the Israel Cancer Association.


  • Chemotaxis
  • MLC phosphorylation
  • Myosin II
  • Myosin II-B phosphorylation
  • PAK1


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