Cloning and increased expression of an insulin receptor substrate-1-like gene in human hepatocellular carcinoma.
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Nishiyama M, Wands JR
Cloning and increased expression of an insulin receptor substrate-1-like gene in human hepatocellular carcinoma.
Biochem Biophys Res Commun. 1992 Feb 28;183(1):280-5.
- PubMed ID
- 1311924 [ View in PubMed]
- Abstract
Human insulin receptor substrate-1 (hIRS-1) cDNAs were cloned from a lambda GT11 expression library using a monoclonal antibody (MAb) produced against a human hepatocellular carcinoma (HCC) cell line (FOCUS). The predicted amino acid sequence derived from both a genomic DNA fragment and the cDNAs showed a 90.5% identity to the previously reported rat IRS-1 cDNA [Sun, X.P. (1991) Nature 352, 73-77]. Multiple potential phosphorylation sites, that suggest an intrinsic function of this molecule in response to insulin action, were highly conserved between the two species. A c.a. 180 kDa hIRS-1 protein was immunoprecipitated and found to be phosphorylated on tyrosine residue(s) following insulin stimulation of HuH-7 HCC cells. Northern blot analysis demonstrated a single c.a. 5 kb transcript in HCC cell lines and tissues. Higher levels of hIRS-1 gene transcripts were observed in HCC tumors compared to adjacent non-involved normal liver.