1-Phosphatidylinositol 3-Kinase Activity is Required for Insulin-Stimulated Glucose Transport But not for RAS Activation in CHO Cells

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 91; no. 16; pp. 7415 - 7419
• Main Authors: Hara, K, Yonezawa, K, Sakaue, H, Ando, A, Kotani, K, Kitamura, T, Kitamura, Y, Ueda, H, Stephens, L, Jackson, T R
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 02.08.1994; National Acad Sciences; National Academy of Sciences
• Subjects: Animals; Antibodies; Biochemistry; Biological Transport - drug effects; Cell lines; Cellular immunity; CHO Cells; Cricetinae; DNA Mutational Analysis; Facilitative glucose transport proteins; Glucose - metabolism; Glucose Transporter Type 1; Insulin; Insulin - pharmacology; Insulin Receptor Substrate Proteins; Memory interference; Monosaccharide Transport Proteins - metabolism; Mutation; Phosphatidylinositol 3-Kinases; Phosphatidylinositol Phosphates - biosynthesis; Phosphoproteins - metabolism; Phosphotransferases (Alcohol Group Acceptor) - genetics; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Proteins; Proto-Oncogene Proteins p21(ras) - metabolism; Receptors; Reproductive system; Rodents; Signal Transduction - drug effects; Structure-Activity Relationship; Ungulates
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.91.16.7415

Insulin stimulation drives the formation of a complex between tyrosine-phosphorylated insulin receptor substrate 1 (IRS-1) and 1-phosphatidylinositol 3-kinase (PI 3-kinase; ATP:1-phosphatidyl-1D-myo-inositol 3-phosphotransferase, EC 2.7.1.137), a heterodimer consisting of regulatory 85-kDa (p85) and catalytic 110-kDa (p110) subunits. This interaction takes place via the phosphorylated YMXM motifs of IRS-1 and the Src homology region 2 (SH2) domains of p85. In this study, the stable overexpression in a Chinese hamster ovary (CHO) cell line of a mutant p85α (Δ p85) protein, which lacks a binding site for p110, disrupted the complex formation between IRS-1 and the catalytic subunit of PI 3-kinase in intact cells during insulin stimulation. Activation of insulin receptor kinase and the tyrosine phosphorylation of IRS-1 remained unaffected. In this cell line, both insulin-stimulated accumulation of phosphatidylinositol 3,4,5-trisphosphate and the insulin-stimulated glucose uptake due to the translocation of GLUT1 glucose transporters were markedly impaired, whereas neither phorbol 12-myristate 13-acetate-stimulated glucose uptake nor the insulin-stimulated activation of RAS was impaired. These results suggest that PI 3-kinase is required for glucose transport in insulin signaling in CHO cells.