Characterization of a multigene-encoded sodium/hydrogen antiporter (sha) from Pseudomonas aeruginosa: its involvement in pathogenesis.
Sha (also known as Mrp/Mnh/Pha) is a Na+/H+ antiporter encoded by a cluster of six or seven genes that probably form a multisubunit transport complex. The Sha system is important for the homeostasis of H+, Na+, and other monovalent cations and plays a critical role in various functions, including alkaliphily, sporulation, and symbiosis. Here, we characterized the sha homologue genes from the opportunistic pathogen Pseudomonas aeruginosa, which exist as a cluster of six genes (PA1054 to PA1059). The gene cluster PA1054 to PA1059, but not the cluster with a deletion of PA1054, complemented a growth defect in the presence of 0.2 M NaCl and a defect in Na+/H+ antiport activity of the Escherichia coli TO114 mutant lacking the three major Na+/H+ antiporters, indicating that genes PA1054 to PA1059 are responsible for Na+/H+ antiport activity. We disrupted PA1054 (a shaA homologue gene) and determined its effect on Na+ tolerance during growth, Na+ efflux, and pathogenicity in mice. Disruption of PA1054 resulted in severe Na+ sensitivity during growth and decreased Na+ efflux activity. In mice, the deletion mutant of PA1054 also exhibited an attenuated virulence in systemic, pulmonary, and urinary tract infections and also a decrease in colonization of the infected organs. From these results, we conclude that the genes PA1054 to PA1059 encode a Na+/H+ antiporter that is largely responsible for Na+ extrusion in P. aeruginosa and has a role in the infection of the pathogen. We propose to designate PA1054 to PA1059 as the sha (sodium hydrogen antiporter) genes, shaABCDEFG.
Kosono
Saori
S
Environmental Molecular Biology Laboratory, RIKEN, Wako, Saitama 351-0198, Japan. kosono@riken.jp
Haga
Koki
K
Tomizawa
Rui
R
Kajiyama
Yusuke
Y
Hatano
Kazuo
K
Takeda
Shinobu
S
Wakai
Yoshimi
Y
Hino
Motohiro
M
Kudo
Toshiaki
T
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D003470:Culture Media; D005260:Female; D017353:Gene Deletion; D008297:Male; D051379:Mice; D005810:Multigene Family; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D012965:Sodium Chloride; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics* / Q000378:metabolism; D014774:Virulence
D001426:Bacterial Proteins; D003470:Culture Media; D017923:Sodium-Hydrogen Exchangers; D012965:Sodium Chloride