Skip to main content

G protein-coupled receptors mediate two functionally distinct pathways of tyrosine phosphorylation in rat 1a fibroblasts. Shc phosphorylation and receptor endocytosis correlate with activation of Erk kinases.

Publication ,  Journal Article
Luttrell, LM; Daaka, Y; Della Rocca, GJ; Lefkowitz, RJ
Published in: J Biol Chem
December 12, 1997

The Ras-dependent activation of Erk kinases by G protein-coupled receptors (GPCRs) is thought to involve tyrosine phosphorylation of docking proteins that serve as scaffolds for the plasma membrane recruitment of Ras guanine nucleotide exchange factors, such as the Grb2-mSos complex. We have investigated the role of two GPCR-regulated tyrosine phosphoproteins, p125(FAK) (FAK) and Shc, in the Ras-dependent activation of Erk kinases by endogenously expressed GPCRs in Rat 1a fibroblasts. Several lines of evidence suggest that tyrosine phosphorylation of FAK and Shc are independently regulated. The GPCRs for lysophosphatidic acid (LPA), thrombin, and bombesin mediate equivalent increases in FAK tyrosine phosphorylation and FAK-Grb2 association. In contrast, only LPA and thrombin receptors significantly stimulate Shc tyrosine phosphorylation and Shc-Grb2 complex formation. Tyrosine phosphorylation of FAK is pertussis toxin-insensitive, can be mimicked by calcium ionophore, and is inhibited by treatment with cytochalasin D, which depolymerizes the actin cytoskeleton. In contrast, tyrosine phosphorylation of Shc is inhibited by pertussis toxin treatment, is not induced by calcium ionophore, and is insensitive to cytochalasin D. In each case, the rapid stimulation of Erk 1/2 correlates with tyrosine phosphorylation of Shc but not of FAK. The dissociation of FAK-Grb2 complex formation from receptor-mediated activation of Erk 1/2 indicates that recruitment of Grb2-mSos to the plasma membrane is not sufficient to mediate rapid Erk activation. Using four mechanistically distinct inhibitors of clathrin-mediated endocytosis, concanavalin A, hypertonic medium, depletion of intracellular potassium, and monodansylcadaverine, we find that GPCR-mediated Erk 1/2 activation is also endocytosis-dependent. Thus, we propose that an additional step involving vesicle-mediated endocytosis is required for the rapid, Ras-dependent activation of Erk kinases in fibroblasts.

Duke Scholars

Altmetric Attention Stats
Dimensions Citation Stats

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

December 12, 1997

Volume

272

Issue

50

Start / End Page

31648 / 31656

Location

United States

Related Subject Headings

  • src Homology Domains
  • Tyrosine
  • Src Homology 2 Domain-Containing, Transforming Protein 1
  • Shc Signaling Adaptor Proteins
  • Receptors, Cell Surface
  • Rats
  • Proteins
  • Protein-Tyrosine Kinases
  • Phosphorylation
  • Mitogen-Activated Protein Kinases
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Luttrell, L. M., Daaka, Y., Della Rocca, G. J., & Lefkowitz, R. J. (1997). G protein-coupled receptors mediate two functionally distinct pathways of tyrosine phosphorylation in rat 1a fibroblasts. Shc phosphorylation and receptor endocytosis correlate with activation of Erk kinases. J Biol Chem, 272(50), 31648–31656. https://doi.org/10.1074/jbc.272.50.31648
Luttrell, L. M., Y. Daaka, G. J. Della Rocca, and R. J. Lefkowitz. “G protein-coupled receptors mediate two functionally distinct pathways of tyrosine phosphorylation in rat 1a fibroblasts. Shc phosphorylation and receptor endocytosis correlate with activation of Erk kinases.J Biol Chem 272, no. 50 (December 12, 1997): 31648–56. https://doi.org/10.1074/jbc.272.50.31648.

Published In

J Biol Chem

DOI

ISSN

0021-9258

Publication Date

December 12, 1997

Volume

272

Issue

50

Start / End Page

31648 / 31656

Location

United States

Related Subject Headings

  • src Homology Domains
  • Tyrosine
  • Src Homology 2 Domain-Containing, Transforming Protein 1
  • Shc Signaling Adaptor Proteins
  • Receptors, Cell Surface
  • Rats
  • Proteins
  • Protein-Tyrosine Kinases
  • Phosphorylation
  • Mitogen-Activated Protein Kinases