Structural and immunological characterization of insulin-like growth factor II binding to im-9 cells

Pratima Misra, Raymond L. Hintz, Ron G. Rosenfeld

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

The structural and immunological properties of the insulin-like growth factor II (IGF-II) receptor on IM-9 lymphoblasts were studied using a combination of competitive binding and affinity cross-linking techniques as well as with a panel of polyclonal and monoclonal antireceptor antibodies. Unlike (IGF-II) binding to the classical type II IGF receptor, [125I] IGF-II binding to IM-9 cells was potently inhibited not only by unlabeled IGF-II, but also by insulin (50Ü inhibition of binding at 2.5 and 1.5 nM, respectively). Affinity cross-linking of [125I] IGF-II to intact cells, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, demonstrated that the over-whelming majority of IGF-II binding was to a type I receptor (apparent mol wt, >300,000 unreduced and 135,000 reduced), with minimal binding to a type II receptor (apparent mol wt,220,000 unreduced and 240,000 reduced). After preincubation with five different antireceptor antibodies, inhibition of [126] IIGF-II binding was comparable to inhibition of [125I]insulinbinding. These studies demonstrate that in IM-9 cells, the majority of IGF-II binding is to a type I receptor with high affinity for both insulin and IGF-II. Whether this is an atypical insulinreceptor or a unique type I receptor remains to be established.

Original languageEnglish (US)
Pages (from-to)1400-1405
Number of pages6
JournalJournal of Clinical Endocrinology and Metabolism
Volume63
Issue number6
DOIs
StatePublished - Dec 1986

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Endocrinology
  • Clinical Biochemistry
  • Biochemistry, medical

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