Insulin receptor substrate 1 mediates the stimulatory effect of insulin on GLUT4 translocation in transfected rat adipose cells

• Published in: The Journal of biological chemistry 1994-11, Vol.269 (45), p.27920-27924
• Main Authors: Quon, M J, Butte, A J, Zarnowski, M J, Sesti, G, Cushman, S W, Taylor, S I
• Format: Article
• Language: English
• Subjects: Adipose Tissue - metabolism; Animals; Base Sequence; Cell Membrane - metabolism; Cells, Cultured; Epididymis; Epitopes - analysis; Glucose Transporter Type 4; Humans; Insulin - pharmacology; Insulin Receptor Substrate Proteins; Kinetics; Male; Molecular Sequence Data; Monosaccharide Transport Proteins - biosynthesis; Monosaccharide Transport Proteins - metabolism; Muscle Proteins; Oligonucleotides, Antisense - pharmacology; Phosphoproteins - biosynthesis; Phosphoproteins - metabolism; Rats; RNA, Catalytic - metabolism; RNA, Messenger - metabolism; Transfection
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(18)46875-5

Insulin signaling is initiated at least in part by activation of the insulin receptor tyrosine kinase and subsequent phosphorylation of cellular substrates such as insulin receptor substrate 1 (IRS-1). Previous studies have focused on the role of IRS-1 in the mitogenic actions of insulin. We have now investigated the possible role of IRS-1 in mediating the effect of insulin to stimulate glucose transport in a physiologically relevant insulin target tissue. In this study, we transfected rat adipose cells in primary culture with an antisense ribozyme directed against rat IRS-1. Expression of the ribozyme in these cells caused a 4.4-fold increase in the concentration of insulin required to achieve half-maximal stimulation of the translocation of cotransfected epitope-tagged GLUT4 without changing the maximal insulin response. Overexpression of human IRS-1 increased the basal cell surface GLUT4 to nearly the maximal level in the absence of insulin. When the ribozyme (specific to rat IRS-1) was cotransfected along with human IRS-1, the insulin dose-response curve was shifted to the left when compared with cells transfected with the ribozyme alone. These data provide strong support for the hypothesis that IRS-1 plays a role in insulin-stimulated glucose transport in insulin-responsive cells.