Glucose increases both the plasma membrane number and phosphorylation of insulin-like growth factor II/mannose 6-phosphate receptors

Qimin Zhang, Per Olof Berggren, Michael Tally

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

We have investigated the effect of glucose on insulin-like growth factor II (IGF-II) binding to, and intracellular phosphorylation of, the IGF- II/mannose 6-phosphate (M6P) receptor in the insulin-secreting cell line RINm5F. Glucose, at a concentration of 3 mM, significantly increased binding of IGF-II to the cells. A further increase of the binding was observed at a glucose concentration of 10 mM. Scatchard analysis showed that the increased binding was caused by an increased number of the receptors rather than changes in affinity. This effect of glucose was also demonstrated in another insulin-secreting cell line HIT as well as in the human erythroleukemia cell line K562. Affinity cross-linking of the RINm5F cells, using 125-IGF-II, revealed increased binding to the IGF-II/M6P receptor induced by glucose. The effect of glucose on IGF-II binding was mimicked by fructose (10 mM), but not by 3-O-methylglucose (10 mM), and was abolished by the protein kinase C (PKC) inhibitor calphostin C, or down-regulation of PKC, but not by the protein phosphatase inhibitor, okadaic acid. Glucose dose dependently stimulated phosphorylation of the IGF-II/M6P receptor, an effect that was inhibited by down-regulation of PKC activity. This study suggests that the distribution of the IGF-II/M6P receptor in insulin-secreting cells can be regulated by glucose-induced phosphorylation, a mechanism mediated by PKC.

Original languageEnglish (US)
Pages (from-to)23703-23706
Number of pages4
JournalJournal of Biological Chemistry
Volume272
Issue number38
DOIs
StatePublished - Sep 19 1997

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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