Sphingomyelin trafficking in Chlamydia pneumoniae-infected cells

Chlamydia pneumoniae is a bacterial obligate intracellular parasite with a developmental cycle common to all members of the genus Chlamydia, Like othe r chlamydiae, the developmental cycle of C. pneumoniae occurs entirely with in a membrane-bound intracellular vacuole, termed an inclusion, that is non -fusogenic with endosomal or lysosomal compartments. To characterize the ve sicular interactions of the C. pneumoniae inclusion, we used a fluorescent analogue of ceramide, (N-[7-(4-nitrobenzo-2-oxa-1,3-diazole)]-6-aminocaproy l-D-erythro-sphingosine (C-6-NBD-Cer), that has previously been used to cha racterize the endogenous synthesis and transport of sphingolipids from the Golgi apparatus to Chlamydia trachomatis and Chlamydia psittaci inclusions. Sphingolipids are trafficked to C. pneumoniae inclusions in a time-, tempe rature- and energy-dependent manner with properties very similar to the del ivery of sphingomyelin to C. trachomatis inclusions. These results indicate that interactions of the inclusion with a subset of sphingomyelin-containi ng exocytic vesicles is a property common to all species of chlamydiae.