title: Human autoantibodies reactive with the signal-recognition particle.
abstract: We describe autoantibodies reactive with the signal-recognition particle (SRP) in serum of a patient with polymyositis. The serum specifically immunoprecipitated the SRP from human erythroleukemia (K562) cell extracts. Analysis of immunoblots revealed that the serum contained autoantibodies specific for the 54-kDa protein of the SRP but had little or no reactivity with its other five proteins. Indirect immunofluorescence of human laryngeal carcinoma (HEp-2) cells confirmed that the ribonucleoprotein immunoprecipitated by this serum is found mainly in the cytoplasm. This autoimmune serum may be useful for studying the function of the 54-kDa subunit of the SRP in binding to signal sequences or in interacting with other components of the translational machinery.
mesh_terms: D000918:Antibody Specificity; D001323:Autoantibodies / Q000276:immunology*; D001327:Autoimmune Diseases / Q000276:immunology*; D003593:Cytoplasm / Q000276:immunology; D006801:Humans; D009220:Myositis / Q000276:immunology*; D012313:RNA / Q000276:immunology*; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins / Q000276:immunology*; D018271:Signal Recognition Particle
chemical_list: D001323:Autoantibodies; D020733:RNA, Small Cytoplasmic; D012261:Ribonucleoproteins; D018271:Signal Recognition Particle; D012313:RNA