title: Factor XIII A is synthesized and expressed on the surface of U937 cells and alveolar macrophages.
abstract: Factor XIII A subunit was detected in U937 cells and human alveolar macrophages by immunohistology and Western blotting. U937 cells synthesize factor XIII A subunit de novo under serum-free, platelet-free conditions, as indicated by 35S-methionine labeling and immunoprecipitation. Thrombin-dependent activity was demonstrated to account for 98% of the total transglutaminase activity in U937 cells (1.5 micrograms per 0.5 X 10(6) cells/mL). Intact U937 cells and alveolar macrophages and homogenates from these cells cross-linked fibrin to form gamma-gamma and alpha-polymers. Factor XIII A was detected on the surface of intact U937 cells and macrophages by flow cytometry and 125I-labeling and immunoprecipitation. Cell surface expression of factor XIII A was augmented in the presence of several soluble macrophage activators; however, no concurrent increase in its biosynthesis was observed. The presence and cell surface expression of factor XIII A subunit within macrophages suggest new pathways by which these cells may function in clotting and in the remodeling of the extracellular matrix during inflammation and wound healing.
mesh_terms: D001777:Blood Coagulation; D002460:Cell Line; D005109:Extracellular Matrix / Q000378:metabolism; D005176:Factor XIII / Q000096:biosynthesis* / Q000276:immunology; D005337:Fibrin / Q000378:metabolism; D006644:Histiocytes / Q000378:metabolism*; D006801:Humans; D007122:Immunoelectrophoresis; D016403:Lymphoma, Large B-Cell, Diffuse / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000378:metabolism* / Q000502:physiology; D008565:Membrane Proteins / Q000096:biosynthesis*; D009363:Neoplasm Proteins / Q000096:biosynthesis; D011650:Pulmonary Alveoli / Q000166:cytology; D011503:Transglutaminases
chemical_list: D008565:Membrane Proteins; D009363:Neoplasm Proteins; D005337:Fibrin; D005176:Factor XIII; D011503:Transglutaminases