SPHINGOLIPIDS AND GLYCOPROTEINS ARE DIFFERENTIALLY TRAFFICKED TO THE CHLAMYDIA-TRACHOMATIS INCLUSION

Chlamydia trachomatis is an obligate intracellular pathogen that multi plies within the confines of a membrane-bound vacuole called an inclus ion. Approximately 40-50% of the sphingomyelin synthesized from exogen ously added NBD-ceramide is specifically transported from the Golgi ap paratus to the chlamydial inclusion (Hackstadt, T., M.A. Scidmore, and D.D. Rockey. 1995. Proc. Natl. Acad. Sci USA. 92: 4877-4881). Given t his major disruption of a cellular exocytic pathway and the similariti es between glycolipid and glycoprotein exocytosis, we wished to determ ine whether the processing and trafficking of glycoproteins through th e Golgi apparatus to the plasma membrane in chlamydia-infected cells w as also disrupted, We analyzed the processing of several model glycopr oteins including vesicular stomatitis virus G-protein, transferrin rec eptor, and human histocompatibility leukocyte class I antigen. In infe cted cells, the posttranslational processing and trafficking of these specific proteins through the Golgi apparatus and subsequent transport to the plasma membrane was not significantly impaired.