Glycosyl-phosphatidylinositol linkage as a mechanism for cell-surface expression of immunoglobulin D.
The B-cell antigen receptor of the IgM and IgD class is a multimeric complex consisting of the membrane-bound form of the immunoglobulin molecule and two other proteins, Ig-alpha and Ig-beta. The Ig-alpha and Ig-beta proteins form a disulphide-linked alpha/beta heterodimer and are encoded by the mb-1 (ref 9, 10) and B29 genes, respectively. Surface expression of the membrane-bound IgM molecule requires assembly with the alpha/beta heterodimer. The IgD molecule, however, can be expressed on the cell surface in an alpha/beta-dependent and -independent form. We show here that in the alpha/beta-independent form the IgD molecule is anchored in the plasma membrane through a glycosyl-phosphatidylinositol linker. In the presence of the alpha/beta heterodimer, most of the otherwise glycosyl-phosphatidylinositol-linked IgD molecule is expressed on the cell surface as transmembrane proteins.
Wienands
J
J
Max-Planck Institut für Immunbiologie, Freiburg, Germany.
Reth
M
M
D001692:Biological Transport; D015153:Blotting, Western; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology*; D003001:Cloning, Molecular; D015870:Gene Expression; D006017:Glycolipids / Q000378:metabolism*; D017261:Glycosylphosphatidylinositols; D007072:Immunoglobulin D / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D046911:Macromolecular Substances; D009101:Multiple Myeloma / Q000276:immunology; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010716:Phosphatidylinositols / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D014162:Transfection
D006017:Glycolipids; D017261:Glycosylphosphatidylinositols; D007072:Immunoglobulin D; D046911:Macromolecular Substances; D010716:Phosphatidylinositols; D010727:Phosphoric Diester Hydrolases; D043265:Phosphatidylinositol Diacylglycerol-Lyase