Rickettsia typhi Possesses Phospholipase A(2) Enzymes that Are Involved in Infection of Host Cells
| dc.contributor | Virginia Tech | en |
| dc.contributor.author | Rahman, M. Sayeedu | en |
| dc.contributor.author | Gillespie, Joseph J. | en |
| dc.contributor.author | Kaur, Simran Jeet | en |
| dc.contributor.author | Sears, Khandra T. | en |
| dc.contributor.author | Ceraul, Shane M. | en |
| dc.contributor.author | Beier-Sexton, Magda | en |
| dc.contributor.author | Azad, Abdu F. | en |
| dc.date.accessioned | 2014-07-01T19:10:28Z | en |
| dc.date.available | 2014-07-01T19:10:28Z | en |
| dc.date.issued | 2013-06-20 | en |
| dc.description.abstract | The long-standing proposal that phospholipase A2 (PLA2) enzymes are involved in rickettsial infection of host cells has been given support by the recent characterization of a patatin phospholipase (Pat2) with PLA2 activity from the pathogens Rickettsia prowazekii and R. typhi. However, pat2 is not encoded in all Rickettsia genomes; yet another uncharacterized patatin (Pat1) is indeed ubiquitous. Here, evolutionary analysis of both patatins across 46 Rickettsia genomes revealed 1) pat1 and pat2 loci are syntenic across all genomes, 2) both Pat1 and Pat2 do not contain predicted Sec-dependent signal sequences, 3) pat2 has been pseudogenized multiple times in rickettsial evolution, and 4) ubiquitous pat1 forms two divergent groups (pat1A and pat1B) with strong evidence for recombination between pat1B and plasmid-encoded homologs. In light of these findings, we extended the characterization of R. typhi Pat1 and Pat2 proteins and determined their role in the infection process. As previously demonstrated for Pat2, we determined that 1) Pat1 is expressed and secreted into the host cytoplasm during R. typhi infection, 2) expression of recombinant Pat1 is cytotoxic to yeast cells, 3) recombinant Pat1 possesses PLA2 activity that requires a host cofactor, and 4) both Pat1 cytotoxicity and PLA2 activity were reduced by PLA2 inhibitors and abolished by site-directed mutagenesis of catalytic Ser/Asp residues. To ascertain the role of Pat1 and Pat2 in R. typhi infection, antibodies to both proteins were used to pretreat rickettsiae. Subsequent invasion and plaque assays both indicated a significant decrease in R. typhi infection compared to that by pre-immune IgG. Furthermore, antibody-pretreatment of R. typhi blocked/delayed phagosomal escapes. Together, these data suggest both enzymes are involved early in the infection process. Collectively, our study suggests that R. typhi utilizes two evolutionary divergent patatin phospholipases to support its intracellular life cycle, a mechanism distinguishing it from other rickettsial species. | en |
| dc.description.sponsorship | The research presented in this manuscript was supported by funds from the National Institute of Health/National Institute of Allergy and Infectious Diseases (AI017828 and AI043006 to AFA). JJG acknowledges support from NIAID award HHSN272200900040C (to Bruno W. Sobral, Virginia Bioinformatics Institute, Virginia Tech). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. | en |
| dc.format.mimetype | application/pdf | en |
| dc.identifier.citation | Rahman MS, Gillespie JJ, Kaur SJ, Sears KT, Ceraul SM, et al. (2013) Rickettsia typhi Possesses Phospholipase A2 Enzymes that Are Involved in Infection of Host Cells. PLoS Pathog 9(6): e1003399. doi:10.1371/journal.ppat.1003399 | en |
| dc.identifier.doi | https://doi.org/10.1371/journal.ppat.1003399 | en |
| dc.identifier.issn | 1553-7374 | en |
| dc.identifier.uri | http://hdl.handle.net/10919/49256 | en |
| dc.identifier.url | http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.1003399 | en |
| dc.language.iso | en | en |
| dc.publisher | Public Library of Science | en |
| dc.rights | Creative Commons CC0 1.0 Universal Public Domain Dedication | en |
| dc.rights.uri | http://creativecommons.org/publicdomain/zero/1.0/ | en |
| dc.subject | Antibodies | en |
| dc.subject | Bacterial genomics | en |
| dc.subject | Cytoplasm | en |
| dc.subject | Genome evolution | en |
| dc.subject | Host cells | en |
| dc.subject | Recombinant proteins | en |
| dc.subject | Rckettsia | en |
| dc.subject | Rickettsia rickettsii | en |
| dc.subject | Sequence alignment | en |
| dc.subject | Signal peptides | en |
| dc.title | Rickettsia typhi Possesses Phospholipase A(2) Enzymes that Are Involved in Infection of Host Cells | en |
| dc.title.serial | PLos Pathogen | en |
| dc.type | Article - Refereed | en |
| dc.type.dcmitype | Text | en |