Evaluation by dot-immunoassay of the differential distribution of cell surface and intracellular proteins in glycosylphosphatidylinositol-rich plasma membrane domains

Anal Biochem. 1996 Mar 1;235(1):49-56. doi: 10.1006/abio.1996.0090.

Abstract

The dot-immunoassay has been adapted for rapid detection and partial characterization of glycosylphosphatidylinositol (GPI)-linked, transmembrane, and intracellular proteins in Triton X-100 (TX-100) extracts of lymphoma cells and intestinal tissue. The GPI-anchored proteins tend to concentrate into specialized plasma membrane domains enriched in glycosphingolipids. The dot-immunoassay has been successfully used to demonstrate the differential distribution of GPI-linked and transmembrane surface glycoproteins of T lymphocytes in sucrose density gradient fractions of TX-100 lysate. The type II transmembrane protein CD26 and the intracellular tyrosine kinase p56lck partially cofractionated with GPI-linked glycoproteins, and the extent to which they partition into GPI-rich plasma membrane domains could be evaluated. Preferential association of the acidic glycosphingolipid GM1 with these domains could be demonstrated by cholera toxin binding directly to the dot-blotted sucrose density gradient fractions. Treatment of whole cell TX-100 lysates or sucrose gradient fractions dotted onto nitrocellulose filter strips with bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) proved to be an efficient method to assay for the presence of a GPI-anchor in Thy-1 and Ly6 surface glycoproteins. We have used three criteria, namely flotation to light density fractions in sucrose gradients, colocalization with GM1, and sensitivity to PI-PLC cleavage, to assess the presence of a GPI modification in a putative GPI-linked protein in intestinal tissue extract. It is envisaged that the techniques described in this report would find a wider application to rapidly assess the contents of GPI-rich plasma membrane domains in different cells and tissues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Membrane / metabolism*
  • Evaluation Studies as Topic
  • Glycosylphosphatidylinositols / metabolism*
  • Immunoassay
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Octoxynol
  • Phosphatidylinositol Diacylglycerol-Lyase
  • Phosphoinositide Phospholipase C
  • Phosphoric Diester Hydrolases / metabolism
  • Sensitivity and Specificity
  • Tumor Cells, Cultured

Substances

  • Glycosylphosphatidylinositols
  • Membrane Proteins
  • Octoxynol
  • Phosphoric Diester Hydrolases
  • Phosphoinositide Phospholipase C
  • Phosphatidylinositol Diacylglycerol-Lyase