Functional characterization of the promoter of pp63, a gene encoding a natural inhibitor of the insulin receptor tyrosine kinase.

PP63 is a liver specific phosphorylated glycoprotein encoded by a single copy gene, which has the property of inhibiting both autophosphorylation and tyrosine kinase activity of the insulin receptor. In this study, we have analyzed the structure activity relationship of the pp63 gene promoter. Five protein binding sites were found in the proximal 5' flanking region of the gene (-223 to +4).

Expression of the pp63 gene encoding the insulin receptor tyrosine kinase inhibitor in proliferating liver and in liver tumors.

After partial hepatectomy in rats, a approximately 4-fold decrease in pp63 mRNA level was detected at 24 h, but not at earlier time points. In mice, during liver cell proliferation induced by 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene and phenobarbital, pp63 transcript levels had a decrease of 40-50%. However, pp63 mRNA was 5-6 fold higher in murine hepatocellular tumors than in normal adult mouse liver.

Primary structure of the rat gene encoding an inhibitor of the insulin receptor tyrosine kinase.

The gene (PP63) encoding the inhibitor (PP63) of the insulin receptor tyrosine kinase was isolated from a rat genomic library. The intron/exon organization was deduced from Southern-blot analysis and sequence data (i.e.

[Transforming growth factor beta in the vitreous of patients with epiretinal proliferation].

Recent evidence suggests that TGF beta, a substance synthetized and released by Retinal Pigment Epithelial (RPE) cells, might play a role in fibrotic preretinal proliferation. We measured the concentration of this factor by radioreceptor assay in samples of vitreous obtained from 17 patients by vitrectomy. Seven had uncomplicated Retinal Detachment (RD) and 10 had either Proliferative Vitreoretinopathy (PVR) or Epimacular Membranes (EM).

Characterization of a natural inhibitor of the insulin receptor tyrosine kinase: cDNA cloning, purification, and anti-mitogenic activity.

Amino acid sequence of the precursor of the phosphorylated N-glycoprotein (pp63) secreted by rat hepatocytes was deduced from the cDNA sequence. This polypeptide (Mr = 40,586) was rich in both cysteine and proline and contained three potential N-glycosylation sites. A single pp63 mRNA species (approximately 2000 bp), found in normal hepatocytes but not in FaO hepatoma cells, appeared to result from transcription of a single gene.