Abstract
Anaplasma phagocytophilum is an emerging human pathogen and obligate intracellular bacterium. It inhabits a host cell-derived vacuole and cycles between replicative reticulate cell (RC) and infectious dense-cored (DC) morphotypes. Host-pathogen interactions that are critical for RC-to-DC conversion are undefined. We previously reported that A.phagocytophilum recruits green fluorescent protein (GFP)-tagged Rab10, a GTPase that directs exocytic traffic from the sphingolipid-rich trans-Golgi network (TGN) to its vacuole in a guanine nucleotide-independent manner. Here, we demonstrate that endogenous Rab10-positive TGN vesicles are not only routed to but also delivered into the A.phagocytophilum-occupied vacuole (ApV). Consistent with this finding, A.phagocytophilum incorporates sphingolipids while intracellular and retains them when naturally released from host cells. TGN vesicle delivery into the ApV is Rab10 dependent, up-regulates expression of the DC-specific marker, APH1235, and is critical for the production of infectious progeny. The A.phagocytophilum surface protein, uridine monophosphate kinase, was identified as a guanine nucleotide-independent, Rab10-specific ligand. These data delineate why Rab10 is important for the A.phagocytophilum infection cycle and expand the understanding of the benefits that exploiting host cell membrane traffic affords intracellular bacterial pathogens.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 260-281 |
| Number of pages | 22 |
| Journal | Cellular Microbiology |
| Volume | 18 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 1 2016 |
Funding
We thank Yasuko Rikihisa (Ohio State University, Columbus, OH) for Asp55 antiserum and her and Qingming Xiong (Ohio State) for helpful advice on density gradient purification. We thank C. Dan Nacu of the Virginia Commonwealth University Department of Communication Arts and Design for producing the model in Fig. 12. We thank Bob Heinzen and Charles Larson for critical review of this manuscript, Scott Henderson for helpful discussions regarding SIM and Christine Van Duyn for technical assistance. This study was supported by funding from NIH grants AI072683 (to J. A. C.), HL125353 (to C. E. C.) and AI109068 (to C. E. C); National Center for Advancing Translational Sciences grant UL1TR000058 (to J. A. C.); the Veteran''s Administration (VA Merit Review I BX001792 to C. E. C. and a Research Career Scientist Award 13F-RCS-002 to C. E. C.); the Israel Binational Science Foundation (BSF2011360 to C. E. C.); the Center for Clinical and Translational Research Endowment Fund of Virginia Commonwealth University (VCU) (to J. A. C.). LSCM and SIM were performed at the VCU Microscopy Facility, which is supported, in part, with funding from NIH-NINDS Center core grant 5P30NS047463 and NIH-NCI Cancer Center Support grant (P30 CA016059). VCU Lipidomics/Metabolomics Core services and products in support of the research project were generated, in part, by the VCU Massey Cancer Center with funding from NIH-NCI Cancer Center Support grant, P30 CA016059.
Keywords
- Anaplasmataceae
- Intracellular parasitism
- Lipidomics
- Nutritional virulence
- Obligate intracellular
- UMPK
ASJC Scopus subject areas
- Microbiology
- Immunology
- Virology