title: Molecular cloning of effector cell protease receptor-1, a novel cell surface receptor for the protease factor Xa.
abstract: Cellular receptors for blood proteases regulate chemotaxis, extracellular proteolysis, and growth behavior of normal and malignant cells. Binding of the coagulation protease factor Xa to leukocytes is contributed by a recently identified molecule, denominated Effector cell Protease Receptor-1 (EPR-1). Monoclonal antibodies were generated against EPR-1+ MOLT13 lymphocytes and selected for reactivity with lymphocyte surface proteins by flow cytometry and with affinity-purified EPR-1 in Western blots. Antibody-based functional cloning of the cDNA for EPR-1 reveals the sequence of a novel molecule encoded by a prominent 1.9-kilobase mRNA. The cDNA predicts a glycoprotein of 337 amino acids, characterized by a unique cysteine-rich extracellular module, a single membrane-spanning domain, and a serine-rich (26%) cytoplasmic tail featuring at least 15 potential phosphorylation sites. Genetically engineered EPR-1 transfectants were recognized by monoclonal antibodies to EPR-1 and bound 125I-factor Xa in a specific and saturable manner (Kd approximately 10-15 nM). In the absence of factor V/Va, EPR-1 transfectants promoted prothrombin activation in a factor Xa concentration-dependent reaction, inhibited by a monoclonal antibody to EPR-1. These findings define EPR-1 as a novel cell surface receptor for factor Xa potentially implicated in protease-dependent cellular effector functions.
authors.affiliation: Department of Immunology, Scripps Research Institute, La Jolla, California 92037.
authors.forename: D C
authors.initials: DC
authors.lastname: Altieri
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D016466:CHO Cells; D002460:Cell Line; D002846:Chromatography, Affinity; D003001:Cloning, Molecular / Q000379:methods; D006224:Cricetinae; D018076:DNA, Complementary / Q000378:metabolism; D015951:Factor Xa / Q000378:metabolism*; D015723:Gene Library; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D007700:Kinetics; D015458:Leukemia, T-Cell; D007962:Leukocytes / Q000378:metabolism; D008969:Molecular Sequence Data; D010980:Platelet Membrane Glycoproteins / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism; D011516:Prothrombin / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism; D000077022:Survivin; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; C107489:BIRC5 protein, human; D018076:DNA, Complementary; D051034:Inhibitor of Apoptosis Proteins; D010980:Platelet Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000077022:Survivin; C045069:factor X receptors; D011516:Prothrombin; D015951:Factor Xa