A phosphatidylinositol-linkage-deficient T-cell mutant contains insulin-sensitive glycosyl-phosphatidylinositol

Biochem J. 1992 Mar 15;282 ( Pt 3)(Pt 3):681-6. doi: 10.1042/bj2820681.

Abstract

Glycosyl-phosphatidylinositol molecules, acting as both signal transduction elements and membrane protein anchors, have been proposed to play a role during T-cell activation. The MVB2 cell line is a mutant, derived from the wild-type T-T hybrid YH.16.33, which has a defect in the biosynthesis of PtdIns-protein linkages. As a consequence, MVB2 mutants are defective in activation through the T-cell receptor. Despite the lack of glycosyl-PtdIns anchors in the mutant MVB2 cells, a comparison of the levels and structural features of the insulin-sensitive glycosyl-PtdIns between the MVB2 and YH.16.33 lineages indicates that both cell lines are identical in this respect. The time course for insulin-responsiveness coincides in both cell lines, with maximal hydrolysis 30 s after insulin addition. The ultimate localization of insulin-regulated glycosyl-PtdIns at the outer surface of the cell membrane is also similar. These data indicate that the glycosyl-PtdIns whose hydrolysis is regulated by insulin is not anchoring proteins at the cell surface of T-lymphocytes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Membrane / metabolism
  • Glucosamine / metabolism
  • Glycolipids / biosynthesis
  • Glycolipids / genetics
  • Glycolipids / physiology*
  • Glycosylphosphatidylinositols
  • Hydrolysis / drug effects
  • Inositol Phosphates / physiology
  • Insulin / metabolism
  • Insulin / pharmacology
  • Insulin / physiology*
  • Iodine Radioisotopes
  • Lipid Metabolism
  • Lymphocyte Activation / physiology
  • Mice
  • Mutation
  • Phosphatidylinositols / biosynthesis
  • Phosphatidylinositols / genetics
  • Phosphatidylinositols / physiology*
  • Polysaccharides / physiology
  • Signal Transduction / physiology
  • T-Lymphocytes / metabolism
  • T-Lymphocytes / physiology*
  • Tritium

Substances

  • Glycolipids
  • Glycosylphosphatidylinositols
  • Inositol Phosphates
  • Insulin
  • Iodine Radioisotopes
  • Phosphatidylinositols
  • Polysaccharides
  • Tritium
  • Glucosamine