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)
Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts.
E
E
Araki
X J
XJ
Sun
B L
BL
Haag
L M
LM
Chuang
Y
Y
Zhang
T L
TL
Yang-Feng
M F
MF
White
C R
CR
Kahn
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D002874:Chromosome Mapping; D002889:Chromosomes, Human, Pair 2; D003001:Cloning, Molecular; D006224:Cricetinae; D004247:DNA; D005333:Fetus; D015870:Gene Expression; D015698:Genomic Library; D006801:Humans; D017403:In Situ Hybridization; D055504:Insulin Receptor Substrate Proteins; D008099:Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D009132:Muscles / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides; D010750:Phosphoproteins / Q000096:biosynthesis / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism; D051381:Rats; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D014162:Transfection
C526292:IRS1 protein, human; D055504:Insulin Receptor Substrate Proteins; C526296:Irs1 protein, rat; D009838:Oligodeoxyribonucleotides; D010750:Phosphoproteins; D012333:RNA, Messenger; D004247:DNA