title: Chlamydia trachomatis homotypic inclusion fusion is promoted by host microtubule trafficking.
abstract: BACKGROUND
  The developmental cycle of the obligate intracellular pathogen Chlamydia is dependant on the formation of a unique intracellular niche termed the chlamydial inclusion. The inclusion is a membrane bound vacuole derived from host cytoplasmic membrane and is modified significantly by the insertion of chlamydial proteins. A unique property of the inclusion is its propensity for homotypic fusion. The vast majority of cells infected with multiple chlamydial elementary bodies (EBs) contain only a single mature inclusion. The chlamydial protein IncA is required for fusion, however the host process involved are uncharacterized.
  
  
  RESULTS
  Here, through live imaging studies, we determined that the nascent inclusions clustered tightly at the cell microtubule organizing center (MTOC) where they eventually fused to form a single inclusion. We established that factors involved in trafficking were required for efficient fusion as both disruption of the microtubule network and inhibition of microtubule trafficking reduced the efficiency of fusion. Additionally, fusion occurred at multiple sites in the cell and was delayed when the microtubule minus ends were either no longer anchored at a single MTOC or when a cell possessed multiple MTOCs.
  
  
  CONCLUSIONS
  The data presented demonstrates that efficient homotypic fusion requires the inclusions to be in close proximity and that this proximity is dependent on chlamydial microtubule trafficking to the minus ends of microtubules.
authors.affiliation: Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Theresa S
authors.initials: TS
authors.lastname: Richards
authors.forename: Andrea E
authors.initials: AE
authors.lastname: Knowlton
authors.forename: Scott S
authors.initials: SS
authors.lastname: Grieshaber
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002690:Chlamydia Infections / Q000378:metabolism* / Q000382:microbiology; D002692:Chlamydia trachomatis / Q000235:genetics / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D002479:Inclusion Bodies / Q000382:microbiology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D022101:Microtubule-Organizing Center / Q000382:microbiology; D008870:Microtubules / Q000382:microbiology*; D021381:Protein Transport
chemical_list: D001426:Bacterial Proteins; C460868:IncA protein, Chlamydia trachomatis; D008565:Membrane Proteins
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