G protein beta gamma subunits stimulate phosphorylation of Shc adapter protein.
Repository Usage Stats
The mechanism of mitogen-activated protein (MAP) kinase activation by pertussis toxin-sensitive Gi-coupled receptors is known to involve the beta gamma subunits of heterotrimeric G proteins (G beta gamma), p21ras activation, and an as-yet-unidentified tyrosine kinase. To investigate the mechanism of G beta gamma-stimulated p21ras activation, G beta gamma-mediated tyrosine phosphorylation was examined by overexpressing G beta gamma or alpha 2-C10 adrenergic receptors (ARs) that couple to Gi in COS-7 cells. Immunoprecipitation of phosphotyrosine-containing proteins revealed a 2- to 3-fold increase in the phosphorylation of two proteins of approximately 50 kDa (designated as p52) in G beta gamma-transfected cells or in alpha 2-C10 AR-transfected cells stimulated with the agonist UK-14304. The latter response was pertussis toxin sensitive. These proteins (p52) were also specifically immunoprecipitated with anti-Shc antibodies and comigrated with two Shc proteins, 46 and 52 kDa. The G beta gamma- or alpha 2-C10 AR-stimulated p52 (Shc) phosphorylation was inhibited by coexpression of the carboxyl terminus of beta-adrenergic receptor kinase (a G beta gamma-binding pleckstrin homology domain peptide) or by the tyrosine kinase inhibitors genistein and herbimycin A, but not by a dominant negative mutant of p21ras. Worthmannin, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K) inhibited phosphorylation of p52 (Shc), implying involvement of PI3K. These results suggest that G beta gamma-stimulated Shc phosphorylation represents an early step in the pathway leading to p21ras activation, similar to the mechanism utilized by growth factor tyrosine kinase receptors.
SubjectAdaptor Proteins, Signal Transducing
Adaptor Proteins, Vesicular Transport
Calcium-Calmodulin-Dependent Protein Kinases
Phosphotransferases (Alcohol Group Acceptor)
Proto-Oncogene Proteins p21(ras)
Receptors, Adrenergic, alpha-2
Shc Signaling Adaptor Proteins
Src Homology 2 Domain-Containing, Transforming Protein 1
Virulence Factors, Bordetella
More InfoShow full item record
James B. Duke Professor of Medicine
The focus of work in this laboratory is on the elucidation of the molecular properties and regulatory mechanisms controlling the function of G protein-coupled receptors. As model systems we utilize the so called adrenergic receptors for adrenaline and related molecules. The goal is to learn the general principles of signal transduction from the outside to the inside of the cell which are involved in systems as diverse as sensory perception, neuro- transmitter and hormonal signaling. Stud
Showing items related by title, author, creator, and subject.
LKB1 Loss induces characteristic patterns of gene expression in human tumors associated with NRF2 activation and attenuation of PI3K-AKT. Kaufman, Jacob; Amann, Joseph M; Park, Kyungho; Arasada, Rajeswara Rao; Li, Haotian; Shyr, Yu; Carbone, David P (Journal of thoracic oncology : official publication of the International Association for the Study of Lung Cancer, 2014-06)Inactivation of serine/threonine kinase 11 (STK11 or LKB1) is common in lung cancer, and understanding the pathways and phenotypes altered as a consequence will aid the development of targeted therapeutic strategies. Gene ...
Amino acid permeases require COPII components and the ER resident membrane protein Shr3p for packaging into transport vesicles in vitro. Kuehn, Margarethe Joanna; Ljungdahl, PO; Schekman, R (J Cell Biol, 1996-11)In S. cerevisiae lacking SHR3, amino acid permeases specifically accumulate in membranes of the endoplasmic reticulum (ER) and fail to be transported to the plasma membrane. We examined the requirements of transport of the ...
Daaka, Y; Lefkowitz, Robert J; Pitcher, JA; Richardson, M; Robishaw, JD; Stoffel, RH (Proc Natl Acad Sci U S A, 1997-03-18)The G protein-coupled receptor (GPCR) kinases (GRKs) phosphorylate and desensitize agonist-occupied GPCRs. GRK2-mediated receptor phosphorylation is preceded by the agonist-dependent membrane association of this enzyme. ...