title: Subcellular localization of rickettsial invasion protein, InvA.
abstract: To understand further the molecular basis of rickettsial host cell invasion, Rickettsia prowazekii invasion gene homolog (invA) has been characterized. Our previous experiments have shown that InvA is an Ap5A pyrophosphatase, a member of the Nudix hydrolase family, which is up-regulated during the internalization, early growth phase, and exit steps during rickettsial mammalian cell infection. In addition to the molecular characterization, subcellular localization of InvA was investigated. InvA-specific antibodies were raised in mice and used for immunoelectron microscopy. The generated antibodies were shown to recognize InvA and by immunogold labeling showed InvA in the cytoplasm of rickettsiae. A cytoplasmic location for InvA would allow for a rapid response to any internal substance and efficient functioning in hydrolysis of toxic metabolic by-products that are accumulated in the rickettsial cytoplasm during host cell invasion. Protecting bacteria from a hazardous environment could enhance their viability and allow them to remain metabolically active, which is a necessary step for the rickettsial obligate intracellular lifestyle.
authors.affiliation: Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland 21201, USA.
authors.forename: Jariyanart
authors.initials: J
authors.lastname: Gaywee
authors.forename: John B
authors.initials: JB
authors.lastname: Sacci
authors.forename: Suzana
authors.initials: S
authors.lastname: Radulovic
authors.forename: Magda S
authors.initials: MS
authors.lastname: Beier
authors.forename: Abdu F
authors.initials: AF
authors.lastname: Azad
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis*; D015153:Blotting, Western; D002522:Chlorocebus aethiops; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D051379:Mice; D008807:Mice, Inbred BALB C; D016253:Microscopy, Immunoelectron; D011755:Pyrophosphatases / Q000032:analysis*; D012283:Rickettsia prowazekii / Q000737:chemistry* / Q000201:enzymology / Q000648:ultrastructure; D012286:Rickettsia typhi / Q000737:chemistry* / Q000201:enzymology / Q000648:ultrastructure; D014709:Vero Cells
chemical_list: D001426:Bacterial Proteins; C075518:invA protein, Bacteria; D011755:Pyrophosphatases