Phosphotyrosine-dependent interaction of SHC and insulin receptor substrate 1 with the NPEY motif of the insulin receptor via a novel non-SH2 domain.
The SHC proteins have been implicated in insulin receptor (IR) signaling. In this study, we used the sensitive two-hybrid assay of protein-protein interaction to demonstrate that SHC interacts directly with the IR. The interaction is mediated by SHC amino acids 1 to 238 and is therefore independent of the Src homology 2 domain. The interaction is dependent upon IR autophosphorylation, since the interaction is eliminated by mutation of the IR ATP-binding site. In addition, mutational analysis of the Asn-Pro-Glu-Tyr (NPEY) motif within the juxtamembrane domain of the IR showed the importance of the Asn, Pro, and Tyr residues to both SHC and IR substrate 1 (IRS-1) binding. We conclude that SHC interacts directly with the IR and that phosphorylation of Tyr-960 within the IR juxtamembrane domain is necessary for efficient interaction. This interaction is highly reminiscent of that of IRS-1 with the IR, and we show that the SHC IR-binding domain can substitute for that of IRS-1 in yeast and COS cells. We identify a homologous region within the IR-binding domains of SHC and IRS-1, which we term the SAIN (SHC and IRS-1 NPXY-binding) domain, which may explain the basis of these interactions. The SAIN domain appears to represent a novel motif which is able to interact with autophosphorylated receptors such as the IR.
Gustafson
T A
TA
Department of Physiology, University of Maryland School of Medicine, Baltimore 21201, USA.
He
W
W
Craparo
A
A
Schaub
C D
CD
O'Neill
T J
TJ
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D003001:Cloning, Molecular; D006801:Humans; D055504:Insulin Receptor Substrate Proteins; D008954:Models, Biological; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010750:Phosphoproteins / Q000378:metabolism*; D019000:Phosphotyrosine; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011972:Receptor, Insulin / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism
C526292:IRS1 protein, human; D055504:Insulin Receptor Substrate Proteins; D010750:Phosphoproteins; D011506:Proteins; D019000:Phosphotyrosine; D014443:Tyrosine; D011972:Receptor, Insulin