IndraLab
Statements
"Here we show that stimulation by insulin of freshly isolated primary adipocytes resulted in the expected rapid tyrosine phosphorylation of the insulin receptor, IRS-1 and IRS-3. Inhibition of PI 3-kinase enhanced the insulin-stimulated phosphorylation of IRS-1 on (i) Tyr(612) and Tyr(941) (p85 binding sites), concomitant with an increased association of the p85 subunit of PI 3-kinase; (ii) Tyr(896) (a Grb2 binding site); and (iii) Tyr(1229) (an SHP-2 binding site), although little or no binding of SHP-2 to IRS-1 was detectable under any conditions."
"Therefore, during insulin stimulation irs-1 undergoes tyrosine phosphorylation, and a portion of tyrosine phosphorylated irs-1 associated with the insulin receptor. The insulin receptor substrate-1 (irs-1) is rapidly phosphorylated on several tyrosine residues by the activated insulin receptor. Insulin signals are mediated through tyrosine phosphorylation of specific proteins such as insulin receptor substrate 1 (irs-1) and shc by the activated insulin receptor (ir)."