RT Journal Article
SR Electronic
T1 Nerve Growth Factor Stimulation of p42/p44 Mitogen-Activated Protein Kinase in PC12 Cells: Role of G<sub>i/o</sub>, G Protein-Coupled Receptor Kinase 2, β-Arrestin I, and Endocytic Processing
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 63
OP 70
DO 10.1124/mol.60.1.63
VO 60
IS 1
A1 Rakhit, Soma
A1 Pyne, Susan
A1 Pyne, Nigel J.
YR 2001
UL http://molpharm.aspetjournals.org/content/60/1/63.abstract
AB In this study, we have shown that nerve growth factor (NGF)-dependent activation of the p42/p44 mitogen-activated protein kinase (p42/p44 MAPK) pathway in PC12 cells can be partially blocked by pertussis toxin (which inactivates the G proteins Gi/o). This suggests that the Trk A receptor may use a G protein-coupled receptor pathway to signal to p42/p44 MAPK. This was supported by data showing that the NGF-dependent activation of p42/p44 MAPK is potentiated in cells transfected with G protein-coupled receptor kinase 2 (GRK2) or β-arrestin I. Moreover, GRK2 is constitutively bound with the Trk A receptor, whereas NGF stimulates the pertussis toxin-sensitive binding of β-arrestin I to the TrkA receptor-GRK2 complex. Both GRK2 and β-arrestin I are involved in clathrin-mediated endocytic signaling to p42/p44 MAPK. Indeed, inhibitors of clathrin-mediated endocytosis (e.g., monodansylcadaverine, concanavalin A, and hyperosmolar sucrose) reduced the NGF-dependent activation of p42/p44 MAPK. Finally, we have found that the G protein-coupled receptor-dependent component regulating p42/p44 MAPK is required for NGF-induced differentiation of PC12 cells. Thus, NGF-dependent inhibition of DNA synthesis was partially blocked by PD098059 (inhibitor of MAPK kinase-1 activation) and pertussis toxin. Our findings are the first to show that the Trk A receptor uses a classic G protein-coupled receptor-signaling pathway to promote differentiation of PC12 cells. NGFnerve growth factorMAPKmitogen-activated protein kinaseIGFinsulin-like growth factorGRKG protein-coupled receptor kinaseGrb-2growth factor receptor binding proteinPI3Kphosphoinositide 3-kinaseLPAlysophosphatidic acidPDGFplatelet-derived growth factorGiinhibitory G proteinGab1growth factor receptor binding protein associated binderHRPhorseradish peroxidaseDMEMDulbecco's modified Eagle's mediumFCSfetal calf serumNP-40Nonidet P-40EGFepidermal growth factorGPCRG protein-coupled receptormSosson of sevenlessc-Srccellular Src tyrosine kinaseMDCmonodansylcadaverine