| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Entomology, University of Wisconsin-Madison, Madison, USA
2 Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
3 Institut de Génétique et Microbiologie, CNRS UMR 8621, Bâtiment 360, Université Paris XI, 91405 Orsay Cedex, France
Correspondence
Mark Blight
mark.blight{at}mac-mail.igmors.u-psud.fr
Proteases play a key role in the interaction between pathogens and their hosts. The bacterial entomopathogen Photorhabdus lives in symbiosis with nematodes that invade insects. Following entry into the insect, the bacteria are released from the nematode gut into the open blood system of the insect. Here they secrete factors which kill the host and also convert the host tissues into food for the replicating bacteria and nematodes. One of the secreted proteins is PrtA, which is shown here to be a repeats-in-toxin (RTX) alkaline zinc metalloprotease. PrtA has high affinity for artificial substrates such as casein and gelatin and can be inhibited by zinc metalloprotease inhibitors. The metalloprotease also shows a calcium- and temperature-dependent autolysis. The prtA gene carries the characteristic RTX repeated motifs and predicts high similarity to proteases from Erwinia chrysanthemi, Pseudomonas aeruginosa and Serratia marcescens. The prtA gene resides in a locus encoding both the protease ABC transporter (prtBCD) and an intervening ORF encoding a protease inhibitor (inh). PrtA activity is detectable 24 h after artificial bacterial infection of an insect, suggesting that the protease may play a key role in degrading insect tissues rather than in overcoming the insect immune system. Purified PrtA also shows cytotoxicity to mammalian cell cultures, supporting its proposed role in bioconversion of the insect cadaver into food for bacterial and nematode development.
The GenBank accession numbers for the W14 and K122 prtA clone sequences reported in this paper are AY230749 and AY230750 respectively.
This article has been cited by other articles:
|
|
 |
|
  S. J. Hinchliffe, S. L. Howard, Y. H. Huang, D. J. Clarke, and B. W. Wren The importance of the Rcs phosphorelay in the survival and pathogenesis of the enteropathogenic yersiniae Microbiology, April 1, 2008; 154(4): 1117 - 1131. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. G. Held, C. N. LaRock, D. A. D'Argenio, C. A. Berg, and C. M. Collins A Metalloprotease Secreted by the Insect Pathogen Photorhabdus luminescens Induces Melanization Appl. Envir. Microbiol., December 1, 2007; 73(23): 7622 - 7628. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. Altincicek, M. Linder, D. Linder, K. T. Preissner, and A. Vilcinskas Microbial Metalloproteinases Mediate Sensing of Invading Pathogens and Activate Innate Immune Responses in the Lepidopteran Model Host Galleria mellonella Infect. Immun., January 1, 2007; 75(1): 175 - 183. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Marokhazi, K. Lengyel, S. Pekar, G. Felfoldi, A. Patthy, L. Graf, A. Fodor, and I. Venekei Comparison of Proteolytic Activities Produced by Entomopathogenic Photorhabdus Bacteria: Strain- and Phase-Dependent Heterogeneity in Composition and Activity of Four Enzymes Appl. Envir. Microbiol., December 1, 2004; 70(12): 7311 - 7320. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. M. Cabral, A. Cherqui, A. Pereira, and N. Simoes Purification and Characterization of Two Distinct Metalloproteases Secreted by the Entomopathogenic Bacterium Photorhabdus sp. Strain Az29 Appl. Envir. Microbiol., July 1, 2004; 70(7): 3831 - 3838. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. M. Meslet-Cladiere, A. Pimenta, E. Duchaud, I. B. Holland, and M. A. Blight In Vivo Expression of the Mannose-Resistant Fimbriae of Photorhabdus temperata K122 during Insect Infection J. Bacteriol., February 1, 2004; 186(3): 611 - 622. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
