Epidermal Growth Factor-mediated Transient Phosphorylation and Membrane Localization of Myosin II-B Are Required for Efficient Chemotaxis

• Published in: The Journal of biological chemistry 2003-10, Vol.278 (41), p.40032-40040
• Main Authors: Ben-Ya'acov, Ami, Ravid, Shoshana
• Format: Article
• Language: English
• Subjects: Biological Transport, Active - drug effects; Cell Line, Tumor; Cell Membrane - metabolism; Cell Size; Chemotaxis - drug effects; Chemotaxis - physiology; Epidermal Growth Factor - pharmacology; Focal Adhesions - drug effects; Focal Adhesions - physiology; Humans; Male; Nonmuscle Myosin Type IIB - chemistry; Nonmuscle Myosin Type IIB - metabolism; Phosphorylation; Prostatic Neoplasms - pathology; Prostatic Neoplasms - physiopathology; Protein Structure, Tertiary; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M306948200

Epidermal growth factor (EGF) stimulation of prostate metastatic tumor cells results in transient phosphorylation and cellular localization of non-muscle myosin heavy chain II-B (NMHC II-B) with kinetics similar to those seen in chemotaxis. We demonstrate that expression of 18- and 72-kDa fragments derived from the NMHC II-B C terminus that contain EGF-dependent NMHC II-B phosphorylation sites serve as dominant-negative mutations for EGF-dependent NMHC II-B phosphorylation and localization. Both fragments inhibited the EGF-dependent phosphorylation by competing with NMHC II-B on the myosin heavy chain kinase. However, only expression of the 72-kDa fragment resulted in cells with abnormalities in cell shape, focal adhesions, and chemotaxis. We found that the 72-kDa (but not 18-kDa) fragment is capable of self-assembly. To our knowledge, these results provide the first strong evidence that EGF-dependent NMHC II-B phosphorylation is required for the cellular localization of NMHC II-B and that NMHC II-B is required for normal cell attachment and for chemotactic response.