Insulin modulates PC-1 processing and recruitment in cultured human cells

C. Menzaghi, R. Di Paola, G. Baj, A. Funaro, A. Arnulfo, T. Ercolino, N. Surico, F. Malavasi, V. Trischitta

Research output: Contribution to journalArticlepeer-review

Abstract

We evaluated whether insulin signaling modulates plasma cell glycoprotein (PC-1) plasma membrane recruitment, posttranslational processing, and gene expression in human cultured cell lines. Insulin induced a fourfold increase (P <0.01) of membrane PC-1 expression by rapid and sensitive mechanism(s). This effect was reduced (P <0.05-0.01) by inhibition of phosphatidyl-inositol 3-kinase (200 nmol/l wortmannin) and S6 kinase (50 nmol/l rapamycin) activities and intracellular trafficking (50 μmol/l monensin) and was not accompanied by PC-1 gene expression changes. Moreover, at Western blot, insulin elicited the appearance, in both plasma membrane and cytosol, of a PC-1-related 146-kDa band (in addition to bands of 163, 117, 106, and 97 kDa observed also in absence of insulin) that was sensitive to endoglycosidase H. Finally, inhibition of PC-1 translocation to plasma membrane, by wortmannin pretreatment, increases insulin-stimulated receptor autophosphorylation. Our data indicate that insulin stimulates PC-1 posttranslational processing and translocation to the plasma membrane, which in turn impairs insulin receptor signaling. Bidirectional cross talk between insulin and PC-1, therefore, takes place, which may be part of the hormone self-desensitization mechanism.

Original languageEnglish
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume284
Issue number3 47-3
Publication statusPublished - Mar 1 2003

Keywords

  • Growth factor and ectoenzyme
  • Insulin desensitization
  • Insulin receptor
  • Insulin resistance
  • Plasma cell glycoprotein-1

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Biochemistry

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