Bombesin, lysophosphatidic acid, and epidermal growth factor rapidly stimulate focal adhesion kinase phosphorylation at Ser-910: requirement for ERK activation.
A rapid increase in the tyrosine phosphorylation of focal adhesion kinase (FAK) has been extensively documented in cells stimulated by multiple signaling molecules, but virtually nothing is known about the regulation of FAK phosphorylation at serine residues. Stimulation of Swiss 3T3 cells with bombesin promoted a striking increase ( approximately 13-fold) in the phosphorylation of FAK at Ser-910, as revealed by site-specific antibodies that recognized the phosphorylated state of this residue. Lysophosphatidic acid and epidermal growth factor (EGF) also stimulated FAK phosphorylation at Ser-910. Direct activation of protein kinase C isoforms with phorbol-12,13-dibutyrate (PDB) also promoted striking phosphorylation of FAK at Ser-910. Treatment with the protein kinase C inhibitor GF I or Ro 31-8220 or chronic exposure to PDB prevented the increase in FAK phosphorylation at Ser-910 induced by bombesin or PDB but not by EGF. Treatment with the ERK inhibitors U0126 and PD98059 prevented FAK phosphorylation at Ser-910 in response to all of the stimuli tested. Furthermore, incubation of activated ERK2 with FAK immunocomplexes leads to FAK phosphorylation at Ser-910 in vitro. Our results demonstrate, for the first time, that stimulation with bombesin, lysophosphatidic acid, PDB, or EGF induces phosphorylation of endogenous FAK at Ser-910 via an ERK-dependent pathway in Swiss 3T3 cells.
Hunger-Glaser
Isabel
I
Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA.
Salazar
Eduardo Perez
EP
Sinnett-Smith
James
J
Rozengurt
Enrique
E
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D001839:Bombesin / Q000494:pharmacology*; D017931:DNA Primers; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D007700:Kinetics; D008246:Lysophospholipids / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000502:physiology; D051379:Mice; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D010766:Phosphorylation; D010768:Phosphoserine; D016133:Polymerase Chain Reaction; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D017931:DNA Primers; D008246:Lysophospholipids; D011993:Recombinant Fusion Proteins; D010768:Phosphoserine; D015240:Phorbol 12,13-Dibutyrate; D004815:Epidermal Growth Factor; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496051:Ptk2 protein, mouse; D001839:Bombesin