Functional association between the insulin receptor and the transmembrane protein-tyrosine phosphatase LAR in intact cells.
The receptor-type protein-tyrosine phosphatase LAR (for leukocyte common antigen-related) has been implicated as a physiological regulator of the insulin receptor. To demonstrate a functional interaction between LAR and the insulin receptor, we incubated CHO cells overexpressing the human insulin receptor with an antibody to the extracellular domain of LAR and ... found a 47% decrease in insulin receptor autophosphorylation and kinase activity. A physical association between LAR and the insulin receptor was then shown by immunoprecipitation of LAR from cell lysates and immunoblotting with antibody to the insulin receptor, or vice versa. Up to 11.8% of the LAR protein in the lysates of CHO cells overexpressing both the insulin receptor and LAR co-immunoprecipitated with the insulin receptor. The LAR/insulin receptor association was related to the level of LAR or insulin receptor overexpression and was increased 6.5-fold by chemical cross-linking and 3.9-fold by treatment with insulin, suggesting that receptor activation influences the affinity of LAR for the insulin receptor. In insulin-stimulated rat liver, LAR was temporally enriched in endosomes with the insulin receptor, and incubation of endosomes with neutralizing LAR antibodies decreased insulin receptor dephosphorylation in situ by 28% (p = 0.01 versus control). These data provide more direct evidence of a role for LAR in the physiological regulation of insulin action at the receptor level.
Mesh Terms:
Animals, CHO Cells, Cricetinae, Cross-Linking Reagents, Endosomes, Epidermal Growth Factor, ErbB Receptors, Humans, Immunologic Techniques, Liver, Macromolecular Substances, Male, Phosphoproteins, Protein Binding, Protein Tyrosine Phosphatases, Rats, Rats, Sprague-Dawley, Receptor, Insulin, Receptor-Like Protein Tyrosine Phosphatases, Class 4, Receptors, Cell Surface, Recombinant Proteins, Signal Transduction
Animals, CHO Cells, Cricetinae, Cross-Linking Reagents, Endosomes, Epidermal Growth Factor, ErbB Receptors, Humans, Immunologic Techniques, Liver, Macromolecular Substances, Male, Phosphoproteins, Protein Binding, Protein Tyrosine Phosphatases, Rats, Rats, Sprague-Dawley, Receptor, Insulin, Receptor-Like Protein Tyrosine Phosphatases, Class 4, Receptors, Cell Surface, Recombinant Proteins, Signal Transduction
J. Biol. Chem.
Date: Jan. 03, 1997
PubMed ID: 8995282
View in: Pubmed Google Scholar
Download Curated Data For This Publication
216238
Switch View:
- Interactions 3