Insulin receptor substrate 1 is required for insulin-mediated mitogenic signal transduction.
Insulin treatment of mammalian cells immediately stimulates the tyrosine phosphorylation of a cellular protein of 185 kDa referred to as pp185 or IRS-1 (insulin receptor substrate 1). The potential role of the IRS-1 protein in insulin signaling has been examined by microinjecting affinity-purified antibodies into living cells. Stably transfected Rat-1 fibroblasts, which overexpress the human insulin receptor, were microinjected and subsequently stimulated with insulin or other growth factors. Progression through the cell cycle was monitored by using a single-cell assay, which employs bromodeoxyuridine labeling of DNA and analysis with immunofluorescence microscopy. Microinjection of anti-IRS-1 antibody completely inhibited incorporation of bromodeoxyuridine into the nuclei of cells stimulated with insulin or insulin-like growth factor I but did not affect cells stimulated with serum or a variety of purified growth factors. These studies indicate that IRS-1 is a critical component of the insulin and insulin-like growth factor I signaling pathways, which lead to DNA synthesis and cell growth.
Rose
D W
DW
Department of Medicine, University of California, San Diego.
Saltiel
A R
AR
Majumdar
M
M
Decker
S J
SJ
Olefsky
J M
JM
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000008:administration & dosage; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D004247:DNA / Q000096:biosynthesis; D004815:Epidermal Growth Factor / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D006801:Humans; D007328:Insulin / Q000378:metabolism* / Q000494:pharmacology; D055504:Insulin Receptor Substrate Proteins; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D008845:Microinjections; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011972:Receptor, Insulin / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D014162:Transfection
D000906:Antibodies; C526292:IRS1 protein, human; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526296:Irs1 protein, rat; D010750:Phosphoproteins; D016222:Fibroblast Growth Factor 2; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D004247:DNA; D011972:Receptor, Insulin