Membrane dynamics of the phosphatidylinositol-anchored form and the transmembrane form of the cell adhesion protein LFA-3.
The cell adhesion glycoprotein LFA-3 is expressed on the cell surface of nucleated cells in both a membrane-spanning form and a glycosyl phosphatidylinositol-anchored form. To determine whether distinct membrane anchors direct the dynamics of a given protein, the turnover of biosynthetically 35S-labeled and biotin surface-labeled LFA-3 molecules was followed. It is shown here that (a) expression of the two LFA-3 forms is regenerated with similar kinetics after enzymatic removal from the cell surface; (b) neither of the distinct LFA-3 molecules undergoes constitutive internalization; and (c) transmembrane and glycosyl phosphatidylinositol-anchored LFA-3 have an unusually long life span with an identical half-life of 50 h. Thus, the type of membrane anchor is not affecting turnover characteristics of a particular cell surface glycoprotein.
Hollander
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Department of Human Microbiology, Sackler School of Medicine, Tel-Aviv University, Israel.
D000581:Amidohydrolases; D000954:Antigens, Surface / Q000302:isolation & purification / Q000378:metabolism*; D001402:B-Lymphocytes; D018968:CD58 Antigens; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006017:Glycolipids / Q000378:metabolism*; D017261:Glycosylphosphatidylinositols; D006801:Humans; D007700:Kinetics; D008562:Membrane Glycoproteins / Q000302:isolation & purification / Q000378:metabolism*; D008715:Methionine / Q000378:metabolism; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D010716:Phosphatidylinositols / Q000378:metabolism*; D011402:Pronase; D013997:Time Factors
D000954:Antigens, Surface; D018968:CD58 Antigens; D006017:Glycolipids; D017261:Glycosylphosphatidylinositols; D008562:Membrane Glycoproteins; D010716:Phosphatidylinositols; D008715:Methionine; D011402:Pronase; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase