Volume 68, Issue 1
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


To understand further the molecular basis of rickettsial host cell invasion, invasion gene homolog () has been characterized. Our previous experiments have shown that InvA is an ApA 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.


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  1. Gaywee J, Xu W-L, Radulovic S, Bessman MJ, Azad AF, 2002. The Rickettsia prowazekii invasion gene homolog (invA) encodes a nudix hydrolase active on adenosine (5′)-pentaphospho-(5′)-adenosine. Mol Cell Proteomics 1 : 179–185. [Google Scholar]
  2. Lee PC, Bochner BR, Ames BN, 1983. AppppA, heat shock stress, and cell oxidation. Proc Natl Acad Sci U S A 80 : 7496–7500. [Google Scholar]
  3. Bochner BR, Lee PC, Wilson SW, Cutler CW, Ames BN, 1984. AppppA and related adenylated nucleotides are synthesized as a consequence of oxidative stress. Cell. 37 : 225–232. [Google Scholar]
  4. McLennan AG, 2000. Dinucleoside polyphosphates-friend or foe? Pharmacol Ther 87 : 73–89. [Google Scholar]
  5. Guranowski A, 2000. Specific and nonspecific enzymes involved in the catabolism of mono- and dinucleoside polyphosphates. Pharmacol Ther 87 : 117–139. [Google Scholar]
  6. Mateo J, Miras-Portugal MT, Rotllan P, 1997. Ecto-enzymatic hydrolysis of diadenosine polyphosphates by cultured adrenomedullary vascular endothelial cells. Am J Physiol 273 : C918–C927. [Google Scholar]
  7. Von Drygalski A, Ogilvie A, 2000. Ecto-diadenosine 5′,5′′′- P1,P4-tetraphosphate (Ap4A)-hydrolase is expressed as an ectoenzyme in a variety of mammalian cells and adds new aspects to the turnover of Ap4A. Biofactors 11 : 179–187. [Google Scholar]
  8. Aguilar JS, Reyes R, Asensio AC, Oakin S, Rotllan P, Miledi R, 2001. Ectoenzymatic breakdown of diadenosine polyphosphates by Xenopus laevis oocytes. Eur J Biochem 268 : 1289–1297. [Google Scholar]
  9. Feussner K, Guranowski A, Kostka S, Wasternack C, 1996. Diadenosine 5′,5′′′-P1,P4-tetraphosphate (Ap4A) hydrolase from tomato (Lycopersicon esculentum cv. Lukullus)—purification, biochemical properties and behaviour during stress. Zeitschr Naturforsch Section C J Biosci 51 : 477–486. [Google Scholar]
  10. Nielsen H, Engelbrecht J, Brunak S, Von Heijne G, 1997. Identification of prokaryotic and eukaryotic signal peptides and prediction of their cleavage sites. Protein Eng 10 : 1–6. [Google Scholar]
  11. Radulovic S, Feng HM, Morovic M, Djelalija B, Popov V, Crocquet-Valdes P, Walker DH, 1996. Isolation of Rickettsia akari from the patient in a region where Mediterranean spotted fever is endemic. Clin Infect Dis 22 : 216–220. [Google Scholar]
  12. Manor E, Carbonetti NH, Silverman DJ, 1994. Rickettsia rickettsii has proteins with cross-reacting epitopes to eukaryotic phospholipase A2 and phospholipase C. Microb Pathog 17 : 99–109. [Google Scholar]

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  • Received : 20 May 2002
  • Accepted : 08 Aug 2002

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