Subcellular localization of rickettsial invasion protein, InvA.
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.
Gaywee
Jariyanart
J
Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland 21201, USA.
Sacci
John B
JB
Radulovic
Suzana
S
Beier
Magda S
MS
Azad
Abdu F
AF
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
D001426:Bacterial Proteins; C075518:invA protein, Bacteria; D011755:Pyrophosphatases