Differential effect of pp120 on insulin endocytosis by two variant insulin receptor isoforms

Sergio L I Calzi, Curtis Choice, Sonia M. Najjar

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume273
Issue number4 36-4
StatePublished - 1997
Externally publishedYes

Fingerprint

Insulin Receptor
Endocytosis
Protein Isoforms
Insulin
Degradation
NIH 3T3 Cells
Fibroblasts
Liver
Amino Acid Sequence
Exons
Cells
Amino Acids
Substrates

Keywords

  • Degradation
  • Hormone
  • Internalization
  • Retroendocytosis

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Biochemistry
  • Physiology (medical)

Cite this

Differential effect of pp120 on insulin endocytosis by two variant insulin receptor isoforms. / Calzi, Sergio L I; Choice, Curtis; Najjar, Sonia M.

In: American Journal of Physiology - Endocrinology and Metabolism, Vol. 273, No. 4 36-4, 1997.

Research output: Contribution to journalArticle

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