Critical roles of a housekeeping sortase of probiotic Bifidobacterium bifidum in bacterium–host cell crosstalk
Eiji Ishikawa,
Tetsuya Yamada,
Kazuaki Yamaji,
Masaki Serata,
Daichi Fujii,
Yoshinori Umesaki,
Hirokazu Tsuji,
Koji Nomoto,
Masahiro Ito,
Nobuhiko Okada,
Masato Nagaoka,
Atsushi Gomi
Affiliations
Eiji Ishikawa
Yakult Central Institute, 5-11 Izumi, Kunitachi-shi, Tokyo 186-8650, Japan; Corresponding author
Tetsuya Yamada
Yakult Central Institute, 5-11 Izumi, Kunitachi-shi, Tokyo 186-8650, Japan
Kazuaki Yamaji
Yakult Central Institute, 5-11 Izumi, Kunitachi-shi, Tokyo 186-8650, Japan
Masaki Serata
Yakult Central Institute, 5-11 Izumi, Kunitachi-shi, Tokyo 186-8650, Japan
Daichi Fujii
Yakult Central Institute, 5-11 Izumi, Kunitachi-shi, Tokyo 186-8650, Japan
Yoshinori Umesaki
Yakult Central Institute, 5-11 Izumi, Kunitachi-shi, Tokyo 186-8650, Japan
Hirokazu Tsuji
Yakult Central Institute, 5-11 Izumi, Kunitachi-shi, Tokyo 186-8650, Japan
Koji Nomoto
Yakult Central Institute, 5-11 Izumi, Kunitachi-shi, Tokyo 186-8650, Japan; Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
Masahiro Ito
Department of Microbiology, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
Nobuhiko Okada
Department of Microbiology, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
Masato Nagaoka
Yakult Central Institute, 5-11 Izumi, Kunitachi-shi, Tokyo 186-8650, Japan
Atsushi Gomi
Yakult Central Institute, 5-11 Izumi, Kunitachi-shi, Tokyo 186-8650, Japan
Summary: Bifidobacterium bifidum YIT 10347 (BF-1) is adhesive in vitro. Here we studied the molecular aspects of the BF-1 adhesion process. We identified and characterized non-adhesive mutants and found that a class E housekeeping sortase was critical for the adhesion to mucin. These mutants were significantly less adhesive to GCIY cells than was the wild type (WT), which protected GCIY cells against acid treatment more than did a non-adhesive mutant. The non-adhesive mutants aberrantly accumulated precursors of putative sortase-dependent proteins (SDPs). Recombinant SDPs bound to mucin. Disruption of the housekeeping sortase influenced expression of SDPs and pilus components. Mutants defective in a pilin or in an SDP showed the same adhesion properties as WT. Therefore, multiple SDPs and pili seem to work cooperatively to achieve adhesion, and the housekeeping sortase is responsible for cell wall anchoring of its substrates to ensure their proper biological function.
