Pasteurella multocida toxin stimulates mitogen-activated protein kinase via G(q/11)-dependent transactivation of the epidermal growth factor receptor.
The dermatonecrotic toxin produced by Pasteurella multocida is one of the most potent mitogenic substances known for fibroblasts in vitro. Exposure to recombinant P. multocida toxin (rPMT) causes phospholipase C-mediated hydrolysis of inositol phospholipids, calcium mobilization, and activation of protein kinase C via a poorly characterized mechanism involving G(q/11) family heterotrimeric G proteins. To determine whether the regulation of G protein pathways contributes to the mitogenic effects of rPMT, we have examined the mechanism whereby rPMT stimulates the Erk mitogen-activated protein kinase cascade in cultured HEK-293 cells. Treatment with rPMT resulted in a dose and time-dependent increase in Erk 1/2 phosphorylation that paralleled its stimulation of inositol phospholipid hydrolysis. Both rPMT- and alpha-thrombin receptor- stimulated Erk phosphorylation were selectively blocked by cellular expression of two peptide inhibitors of G(q/11) signaling, the dominant negative mutant G protein-coupled receptor kinase, GRK2(K220R), and the Galpha(q) carboxyl-terminal peptide, Galpha(q)-(305-359). Like alpha-thrombin receptor-mediated Erk activation, the effect of rPMT was insensitive to the protein kinase C inhibitor GF109203X, but was blocked by the epidermal growth factor receptor-specific tyrphostin, AG1478 and by dominant negative mutants of mSos1 and Ha-Ras. These data indicate that rPMT employs G(q/11) family heterotrimeric G proteins to induce Ras-dependent Erk activation via protein kinase C-independent "transactivation" of the epidermal growth factor receptor.
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Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
Choy
E W
EW
Maudsley
S
S
Miller
W E
WE
Wilson
B A
BA
Luttrell
L M
LM
D001426:Bacterial Proteins; D001427:Bacterial Toxins / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D006868:Hydrolysis; D008246:Lysophospholipids / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008934:Mitogens / Q000378:metabolism*; D009154:Mutation; D010716:Phosphatidylinositols / Q000378:metabolism; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins / Q000378:metabolism; D013917:Thrombin / Q000494:pharmacology; D013997:Time Factors; D015533:Transcriptional Activation; D014162:Transfection; D010566:Virulence Factors, Bordetella / Q000378:metabolism; D051552:beta-Adrenergic Receptor Kinases
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D008246:Lysophospholipids; D008934:Mitogens; C062258:Pasteurella multocida toxin; D010716:Phosphatidylinositols; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D010566:Virulence Factors, Bordetella; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D017868:Cyclic AMP-Dependent Protein Kinases; D051552:beta-Adrenergic Receptor Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D013917:Thrombin; D019204:GTP-Binding Proteins