Human autoantibodies to a novel Golgi protein golgin-67: High similarity with golgin-95/gm 130 autoantigen

Autoantibodies to subcellular organelles have been described in patients wi th various systemic rheumatic diseases and our laboratories have been focus ed on studies of the Golgi complex as the autoimmune target. We have previo usly isolated and described four of the five known Golgi autoantigens repor ted to date. During the characterization of Golgi autoantigen golgin-95/gm1 30, another human cDNA that shared a significant degree of similarity in bo th nucleotide and amino acid sequences was identified. Analysis of cDNAs fr om different libraries suggested that this is a distinct gene encoding a pr otein of 67 kDa which has four regions with sequence identity to gm130; ran ging between 42 and 60%. Ln this report, we describe the complete cDNA enco ding a closely related Golgi protein provisionally named golgin-67. Among a group of 84 human anti-Golgi sera, five (6%) were shown to recognize golgi n-67. Anti-golgin-67 human sera and affinity purified rabbit antibody to th e recombinant protein gave predominant Golgi staining. Golgin-67 is thus th e smallest member of a growing family of Golgi autoantigens rich in alpha-h elical coiled-coil domain. The current hypothesis for the generation of aut oimmune antibody to the Golgi complex is discussed. (C) 2000 Academic Press .