Phosphoinositide 3-kinase-dependent membrane recruitment of p62(dok) is essential for its negative effect on mitogen-activated protein (MAP) kinase activation.
A major pathway by which growth factors, such as platelet-derived growth factor (PDGF), regulate cell proliferation is via the receptor tyrosine kinase/Ras/mitogen-activated protein kinase (MAPK) signaling cascade. The output of this pathway is subjected to tight regulation of both positive and negative regulators. One such regulator is p62(dok), the prototype of a newly identified family of adaptor proteins. We recently provided evidence, through the use of p62(dok)-deficient cells, that p62(dok) acts as a negative regulator of growth factor-induced cell proliferation and the Ras/MAPK pathway. We show here that reintroduction of p62(dok) into p62(dok)-(/)- cells can suppress the increased cell proliferation and prolonged MAPK activity seen in these cells, and that plasma membrane recruitment of p62(dok) is essential for its function. We also show that the PDGF-triggered plasma membrane translocation of p62(dok) requires activation of phosphoinositide 3-kinase (PI3-kinase) and binding of its pleckstrin homology (PH) domain to 3'-phosphorylated phosphoinositides. Furthermore, we demonstrate that p62(dok) can exert its negative effect on the PDGFR/MAPK pathway independently of its ability to associate with RasGAP and Nck. We conclude that p62(dok) functions as a negative regulator of the PDGFR/Ras/MAPK signaling pathway through a mechanism involving PI3-kinase-dependent recruitment of p62(dok) to the plasma membrane.
Zhao
M
M
Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
Schmitz
A A
AA
Qin
Y
Y
Di Cristofano
A
A
Pandolfi
P P
PP
Van Aelst
L
L
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001665:Binding Sites; D001693:Biological Transport, Active / Q000187:drug effects; D002455:Cell Division; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004268:DNA-Binding Proteins; D004789:Enzyme Activation; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D018345:Mice, Knockout; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D015513:Oncogene Proteins / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D010982:Platelet-Derived Growth Factor / Q000378:metabolism / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins; D051381:Rats; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism; D015398:Signal Transduction; D020703:ras GTPase-Activating Proteins / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; C489560:DOK1 protein, human; C489561:Dok1 protein, mouse; C074561:GAP-associated protein p62; C078332:Nck protein; D015513:Oncogene Proteins; D010716:Phosphatidylinositols; D010750:Phosphoproteins; D010982:Platelet-Derived Growth Factor; D016601:RNA-Binding Proteins; D020703:ras GTPase-Activating Proteins; D019869:Phosphatidylinositol 3-Kinases; D017479:Receptors, Platelet-Derived Growth Factor; D020928:Mitogen-Activated Protein Kinases; D018631:ras Proteins