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The putative Poc complex controls two distinct P seudomonas aeruginosa polar motility mechanisms
Author(s) -
Cowles Kimberly N.,
Moser Theresa S.,
Siryaporn Albert,
Nyakudarika Natsai,
Dixon William,
Turner Jonathan J.,
Gitai Zemer
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12403
Subject(s) - flagellum , pilus , motility , biology , microbiology and biotechnology , mutant , gene , genetics , escherichia coli
Summary Each P seudomonas aeruginosa cell localizes two types of motility structures, a single flagellum and one or two clusters of type IV pili, to the cell poles. Previous studies suggested that these motility structures arrive at the pole through distinct mechanisms. Here we performed a swimming motility screen to identify polar flagellum localization factors and discovered three genes homologous to the TonB / ExbB / ExbD complex that have defects in both flagella‐mediated swimming and pilus‐mediated twitching motility. We found that deletion of tonB3 , PA 2983 or PA 2982 led to non‐polar localization of the flagellum and FlhF , which was thought to sit at the top of the flagellar localization hierarchy. Surprisingly, these mutants also exhibited pronounced changes in pilus formation or localization, indicating that these proteins may co‐ordinate both the pilus and flagellum motility systems. Thus, we have renamed PA 2983 and PA 2982, pocA and pocB , respectively, for p olar o rganelle c o‐ordinator to reflect this function. Our results suggest that TonB 3, PocA and PocB may form a membrane‐associated complex, which we term the Poc complex. These proteins do not exhibit polar localization themselves, but are required for increased expression of pilus genes upon surface association, indicating that they regulate motility structures through either localization or transcriptional mechanisms.