title: Role for the SRC family kinase Fyn in sphingolipid acquisition by chlamydiae.
abstract: The bacterial obligate intracellular pathogen Chlamydia trachomatis replicates within a membrane-bound vacuole termed the inclusion. From within this protective environment, chlamydiae usurp numerous functions of the host cell to promote chlamydial survival and replication. Here we utilized a small interfering RNA (siRNA)-based screening protocol designed to identify host proteins involved in the trafficking of sphingomyelin to the chlamydial inclusion. Twenty-six host proteins whose deficiency significantly decreased sphingomyelin trafficking to the inclusion and 16 proteins whose deficiency significantly increased sphingomyelin trafficking to the inclusion were identified. The reduced sphingomyelin trafficking caused by downregulation of the Src family tyrosine kinase Fyn was confirmed in more-detailed analyses. Fyn silencing did not alter sphingomyelin synthesis or trafficking in the absence of chlamydial infection but reduced the amount of sphingomyelin trafficked to the inclusion in infected cells, as determined by two independent quantitative assays. Additionally, inhibition of Src family kinases resulted in increased cellular retention of sphingomyelin and significantly decreased incorporation into elementary bodies of both C. trachomatis and Chlamydophila caviae.
authors: Host-Parasite Interactions Section, Laboratory of Intracellular Parasites, NIAID, NIH, Rocky Mountain Laboratories, 903 South 4th Street, Hamilton, MT 59840, USA.
authors: Jeffrey
authors: J
authors: Mital
authors: Ted
authors: T
authors: Hackstadt
mesh_terms: D001692:Biological Transport / Q000502:physiology*; D002692:Chlamydia trachomatis / Q000235:genetics / Q000378:metabolism*; D023501:Chlamydophila / Q000378:metabolism*; D020868:Gene Silencing; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D050356:Lipid Metabolism; D051076:Proto-Oncogene Proteins c-fyn / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering; D013109:Sphingomyelins / Q000378:metabolism*
chemical_list: D034741:RNA, Small Interfering; D013109:Sphingomyelins; C494957:FYN protein, human; D051076:Proto-Oncogene Proteins c-fyn