Shc is a substrate of the rat intestinal epidermal growth factor receptor tyrosine kinase.
OBJECTIVE
Epidermal growth factor (EGF) has been shown to induce intestinal proliferation and maturation; however, little information is available regarding substrates of the intestinal EGF receptor tyrosine kinase. The purpose of this study was to determine if src homologous collagen-like protein (Shc) was an in vivo substrate of the intestinal EGF receptor.


METHODS
Ten-day-old rats were treated with EGF or were breast-fed. In some experiments, IEC-6 cells were treated with EGF. Intestinal tissue and cell fractions were studied by immunodetection to compare the tyrosine phosphorylation state and the subcellular localization of intestinal proteins.


RESULTS
The total tyrosine phosphorylation state of intestinal proteins was increased threefold by EGF. Tyrosine phosphorylation of the EGF receptor and Shc were rapidly increased by EGF. The association of Grb2 with Shc increased fourfold and fivefold. Plasma membrane translocation of Shc and associated phosphotyrosyl proteins was increased within 30 seconds of EGF treatment.


CONCLUSIONS
Shc is a substrate of the intestinal EGF receptor in vivo. EGF-induced association of Shc with the adapter protein Grb2 may have implications for activation of the p21ras signaling pathway in the intestine. The EGF-induced membrane association of Shc with two other phosphotyrosyl proteins suggests involvement of Shc in additional aspects of EGF-receptor signaling in the intestine.
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002352:Carrier Proteins; D002478:Cells, Cultured; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000378:metabolism*; D051380:GRB2 Adaptor Protein; D015151:Immunoblotting; D007413:Intestinal Mucosa / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D014443:Tyrosine / Q000378:metabolism; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D051380:GRB2 Adaptor Protein; C495950:Grb2 protein, rat; D011506:Proteins; C007105:c1q-binding proteins; D014443:Tyrosine; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases