Phospholipase C-gamma, protein kinase C and Ca2+/calmodulin-dependent protein kinase II are involved in platelet-derived growth factor-induced phosphorylation of Tiam1.
In Swiss 3T3 fibroblasts, the Rac1-specific guanine nucleotide exchange factor Tiam1 is phosphorylated by several different agonists. We show here that PDGF induces threonine phosphorylation of Tiam1 in a time- and dose-dependent manner. Tiam1 phosphorylation was significantly reduced by the selective protein kinase C inhibitor Ro-31-8220 and by KN93, an inhibitor of Ca2+/calmodulin-dependent protein kinase II. The Ca2+ chelator BAPTA/AM totally abrogated Tiam1 phosphorylation, indicating that Ca2+ is essential for this phosphorylation. Moreover, PDGF-stimulated Tiam1 phosphorylation was markedly reduced by 72 +/- 10% in PLC-gamma1 deficient mouse fibroblasts, compared to wild-type cells, indicating that phosphoinositide phospholipase C is involved.
Fleming
I N
IN
Howard Hughes Medical Institute and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
Elliott
C M
CM
Exton
J H
JH
D016475:3T3 Cells; D000818:Animals; D001596:Benzylamines / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D020662:Guanine Nucleotide Exchange Factors; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism*; D051379:Mice; D051966:Phospholipase C gamma; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D015398:Signal Transduction; D013379:Substrate Specificity; D013449:Sulfonamides / Q000494:pharmacology; D000075684:T-Lymphoma Invasion and Metastasis-inducing Protein 1; D013912:Threonine / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism*; D000096926:Benzenesulfonamides
D001596:Benzylamines; D002118:Calcium; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D004533:Egtazic Acid; D020662:Guanine Nucleotide Exchange Factors; D007211:Indoles; D007527:Isoenzymes; D051966:Phospholipase C gamma; D010982:Platelet-Derived Growth Factor; D011493:Protein Kinase C; D011506:Proteins; D013449:Sulfonamides; D000075684:T-Lymphoma Invasion and Metastasis-inducing Protein 1; D013912:Threonine; D010738:Type C Phospholipases; C513260:Tiam1 protein, mouse; C072105:KN 93; D000096926:Benzenesulfonamides; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; C064758:Ro 31-8220