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Human skeletal muscle insulin receptor substrate-1. Characterization of the cDNA, gene, and chromosomal localization.

Insulin receptor substrate-1 is a major substrate of insulin receptor Tyr kinase. We have now cloned the IRS-1 cDNA from human skeletal muscle, one of the most important target tissues of insulin action, localized and cloned the human IRS-1 gene, and studied the expression of the protein in Chinese hamster ovary cells. Human IRS-1 cDNA encodes a 1242 amino acid sequence that is 88% identical with rat liver IRS-1. The 14 potential Tyr phosphorylation sites include 6 Tyr-Met-X-Met motifs and 3 Tyr-X-X-Met motifs that are completely conserved in human IRS-1. Human IRS-1 has > 50 possible Ser/Thr phosphorylation sites and one potential ATP-binding site close to the NH2-terminal. The human IRS-1 gene contains the entire 5'-untranslated region and protein coding region in a single exon and was localized on chromosome 2 q36-37 by in situ hybridization. By Northern blot analysis, IRS-1 mRNA is rare and consists of two species of 6.9 and 6 kilobase. By using quantitative polymerase chain reaction after reverse transcription of total RNA from human fetal tissues, IRS-1 mRNA could be identified in all tissues. When human IRS-1 cDNA was expressed in Chinese hamster ovary cells, the protein migrated between 170,000-180,000 M(r) in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and was rapidly Tyr phosphorylated upon insulin stimulation. Thus, IRS-1 is widely expressed and highly conserved across species and tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Pubmed ID: 8513971


  • Araki E
  • Sun XJ
  • Haag BL
  • Chuang LM
  • Zhang Y
  • Yang-Feng TL
  • White MF
  • Kahn CR



Publication Data

July 19, 1993

Associated Grants

  • Agency: NIDDK NIH HHS, Id: DK33201
  • Agency: NIDDK NIH HHS, Id: DK36836
  • Agency: NIDDK NIH HHS, Id: DK43808

Mesh Terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • CHO Cells
  • Chromosome Mapping
  • Chromosomes, Human, Pair 2
  • Cloning, Molecular
  • Cricetinae
  • DNA
  • Fetus
  • Gene Expression
  • Genomic Library
  • Humans
  • In Situ Hybridization
  • Insulin Receptor Substrate Proteins
  • Liver
  • Molecular Sequence Data
  • Muscles
  • Oligodeoxyribonucleotides
  • Phosphoproteins
  • Polymerase Chain Reaction
  • RNA, Messenger
  • Rats
  • Sequence Homology, Amino Acid
  • Transcription, Genetic
  • Transfection