Ezrin is a downstream effector of trafficking PKC-integrin complexes involved in the control of cell motility.

Abstract

Protein kinase C (PKC) alpha has been implicated in beta1 integrin-mediated cell migration. Stable expression of PKCalpha is shown here to enhance wound closure. This PKC-driven migratory response directly correlates with increased C-terminal threonine phosphorylation of ezrin/moesin/radixin (ERM) at the wound edge. Both the wound migratory response and ERM phosphorylation are dependent upon the catalytic function of PKC and are susceptible to inhibition by phosphatidylinositol 3-kinase blockade. Upon phorbol 12,13-dibutyrate stimulation, green fluorescent protein-PKCalpha and beta1 integrins co-sediment with ERM proteins in low-density sucrose gradient fractions that are enriched in transferrin receptors. Using fluorescence lifetime imaging microscopy, PKCalpha is shown to form a molecular complex with ezrin, and the PKC-co-precipitated endogenous ERM is hyperphosphorylated at the C-terminal threonine residue, i.e. activated. Electron microscopy showed an enrichment of both proteins in plasma membrane protrusions. Finally, overexpression of the C-terminal threonine phosphorylation site mutant of ezrin has a dominant inhibitory effect on PKCalpha-induced cell migration. We provide the first evidence that PKCalpha or a PKCalpha-associated serine/threonine kinase can phosphorylate the ERM C-terminal threonine residue within a kinase-ezrin molecular complex in vivo.

• Authors: T Ng, M Parsons, W E Hughes, J Monypenny, D Zicha, A Gautreau, M Arpin, S Gschmeissner, P J Verveer, P I Bastiaens, P J Parker
• Journal: The EMBO journal (EMBO J) Vol. 20 Issue 11 Pg. 2723-41 (Jun 01 2001) ISSN: 0261-4189 [Print] England
• PMID: 11387207 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Chromones
• Cytoskeletal Proteins
• Enzyme Inhibitors
• Integrin beta1
• Isoenzymes
• Luminescent Proteins
• Morpholines
• Phosphoproteins
• Recombinant Fusion Proteins
• ezrin
• Phosphothreonine
• Green Fluorescent Proteins
• 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
• Phorbol 12,13-Dibutyrate
• Phosphatidylinositol 3-Kinases
• PRKCA protein, human
• Protein Kinase C
• Protein Kinase C-alpha

Topics

• Amino Acid Substitution
• Breast Neoplasms
• Cell Membrane (metabolism, ultrastructure)
• Cell Movement (drug effects, physiology)
• Chromones (pharmacology)
• Cytoskeletal Proteins
• Enzyme Inhibitors (pharmacology)
• Female
• Green Fluorescent Proteins
• Humans
• Integrin beta1 (physiology)
• Isoenzymes (metabolism)
• Kinetics
• Luminescent Proteins (analysis, genetics)
• Microscopy, Confocal
• Morpholines (pharmacology)
• Mutagenesis, Site-Directed
• Phorbol 12,13-Dibutyrate (pharmacology)
• Phosphatidylinositol 3-Kinases (metabolism)
• Phosphoproteins (chemistry, metabolism)
• Phosphorylation
• Phosphothreonine (metabolism)
• Protein Kinase C (metabolism)
• Protein Kinase C-alpha
• Recombinant Fusion Proteins (analysis, biosynthesis, chemistry)
• Tumor Cells, Cultured
• Wound Healing (physiology)