Differential effect of pp120 on insulin endocytosis by two variant insulin receptor isoforms
American Journal of Physiology-Endocrinology and Metabolism, 1997•journals.physiology.org
The insulin receptor is expressed as two variably spliced isoforms that differ by the absence
(isoform A) or presence (isoform B) of a 12-amino acid sequence encoded by exon 11 at the
carboxy terminus of the α-subunit. Coexpression of the A isoform and pp120, a substrate of
the insulin receptor tyrosine kinase, in NIH 3T3 fibroblasts increased receptor A-mediated
insulin endocytosis and degradation by two-to threefold compared with cells expressing
receptors alone. Because B is the predominant isoform in the liver and binds insulin with …
(isoform A) or presence (isoform B) of a 12-amino acid sequence encoded by exon 11 at the
carboxy terminus of the α-subunit. Coexpression of the A isoform and pp120, a substrate of
the insulin receptor tyrosine kinase, in NIH 3T3 fibroblasts increased receptor A-mediated
insulin endocytosis and degradation by two-to threefold compared with cells expressing
receptors alone. Because B is the predominant isoform in the liver and binds insulin with …
The insulin receptor is expressed as two variably spliced isoforms that differ by the absence (isoform A) or presence (isoform B) of a 12-amino acid sequence encoded by exon 11 at the carboxy terminus of the α-subunit. Coexpression of the A isoform and pp120, a substrate of the insulin receptor tyrosine kinase, in NIH 3T3 fibroblasts increased receptor A-mediated insulin endocytosis and degradation by two- to threefold compared with cells expressing receptors alone. Because B is the predominant isoform in the liver and binds insulin with lower affinity than A, we have examined the effect of pp120 on receptor B-mediated endocytosis. In contrast to isoform A, the effect of pp120 on isoform B-mediated insulin internalization and degradation in stably transfected NIH 3T3 cells was minimal.
American Physiological Society