Isolation and characterization of a novel 68,000-Mr Ca2+-binding protein of lymphocyte plasma membrane.
A 68 000-Mr protein is a major component of a Nonidet P-40-insoluble fraction of lymphocyte plasma membrane prepared from human B lymphoblastoid cells ( BRI 8) and pig mesenteric lymph nodes. The association of the protein with the detergent-insoluble complex depends on free Ca2+ concentrations of greater than 10 microM. The human and pig 68 000-Mr proteins were purified and appear to be homologous on the basis of amino acid composition and peptide mapping. The protein is monomeric, has pI 5.8 and a single high-affinity Ca2+-binding site (KD 1.2 microM). The results are discussed in terms of the possible role of the 68 000-Mr protein as an intracellular Ca2+ receptor in lymphocytes.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D017317:Annexin A6; D002135:Calcium-Binding Proteins / Q000302:isolation & purification; D002460:Cell Line; D002462:Cell Membrane / Q000032:analysis; D002850:Chromatography, Gel; D004533:Egtazic Acid; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008214:Lymphocytes / Q000032:analysis*; D008565:Membrane Proteins / Q000302:isolation & purification; D008970:Molecular Weight; D017830:Octoxynol; D011092:Polyethylene Glycols; D013552:Swine
D000596:Amino Acids; D017317:Annexin A6; D002135:Calcium-Binding Proteins; D008565:Membrane Proteins; D011092:Polyethylene Glycols; D004533:Egtazic Acid; D017830:Octoxynol; C010615:Nonidet P-40