The insulin receptor juxtamembrane region contains two independent tyrosine/beta-turn internalization signals.
Open Access
- 15 August 1992
- journal article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 118 (4), 831-839
- https://doi.org/10.1083/jcb.118.4.831
Abstract
We have investigated the role of tyrosine residues in the insulin receptor cytoplasmic juxtamembrane region (Tyr953 and Tyr960) during endocytosis. Analysis of the secondary structure of the juxtamembrane region by the Chou-Fasman algorithms predicts that both the sequences GPLY953 and NPEY960 form tyrosine-containing beta-turns. Similarly, analysis of model peptides by 1-D and 2-D NMR show that these sequences form beta-turns in solution, whereas replacement of the tyrosine residues with alanine destabilizes the beta-turn. CHO cell lines were prepared expressing mutant receptors in which each tyrosine was mutated to phenylalanine or alanine, and an additional mutant contained alanine at both positions. These mutations had no effect on insulin binding or receptor autophosphorylation. Replacements with phenylalanine had no effect on the rate of [125I]insulin endocytosis, whereas single substitutions with alanine reduced [125I]insulin endocytosis by 40-50%. Replacement of both tyrosines with alanine reduced internalization by 70%. These data suggest that the insulin receptor contains two tyrosine/beta-turns which contribute independently and additively to insulin-stimulated endocytosis.Keywords
This publication has 45 references indexed in Scilit:
- Insulin receptors internalize by a rapid, saturable pathway requiring receptor autophosphorylation and an intact juxtamembrane region.The Journal of cell biology, 1991
- Endocytosis of the ASGP receptor H1 is reduced by mutation of tyrosine-5 but still occurs via coated pits.The Journal of cell biology, 1991
- Mutagenesis of the human transferrin receptor: two cytoplasmic phenylalanines are required for efficient internalization and a second-site mutation is capable of reverting an internalization-defective phenotype.The Journal of cell biology, 1991
- Role of the human transferrin receptor cytoplasmic domain in endocytosis: localization of a specific signal sequence for internalization.The Journal of cell biology, 1990
- Deletion of the cytoplasmic domain of the polymeric immunoglobulin receptor prevents basolateral localization and endocytosisCell, 1986
- Intracellular pathway followed by the insulin receptor covalently coupled to 125I-photoreactive insulin during internalization and recycling.The Journal of cell biology, 1986
- Receptor-Mediated Endocytosis: Concepts Emerging from the LDL Receptor SystemAnnual Review of Cell Biology, 1985
- Internalization-defective LDL receptors produced by genes with nonsense and frameshift mutations that truncate the cytoplasmic domainCell, 1985
- Human insulin receptor and its relationship to the tyrosine kinase family of oncogenesNature, 1985
- Coated vesicles participate in the receptor-mediated endocytosis of insulin.The Journal of cell biology, 1983