Premium
Activation of Rho through a cross‐link with polyamines catalyzed by Bordetella dermonecrotizing toxin
Author(s) -
Masuda Minako,
Betancourt Lazaro,
Matsuzawa Takeshi,
Kashimoto Takashige,
Takao Toshifumi,
Shimonishi Yasutsugu,
Horiguchi Yasuhiko
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.4.521
Subject(s) - spermine , gtpase , cdc42 , polyamine , putrescine , spermidine , gtp' , chemistry , biochemistry , microbiology and biotechnology , effector , deamidation , rac1 , clostridium difficile toxin b , biology , clostridium difficile toxin a , enzyme , signal transduction , clostridium difficile , antibiotics
The small GTPase Rho, which regulates a variety of cell functions, also serves as a specific substrate for bacterial toxins. Here we demonstrate that Bordetella dermonecrotizing toxin (DNT) catalyzes cross‐linking of Rho with ubiquitous polyamines such as putrescine, spermidine and spermine. Mass spectrometric analyses revealed that the cross‐link occurred at Gln63, which had been reported to be deamidated by DNT in the absence of polyamines. Rac1 and Cdc42, other members of the Rho family GTPases, were also polyaminated by DNT. The polyamination, like the deamidation, markedly reduced the GTPase activity of Rho without affecting its GTP‐binding activity, indicating that polyaminated Rho behaves as a constitutively active analog. Moreover, polyamine‐linked Rho, even in the GDP‐bound form, associated more effectively with its effector ROCK than deamidated Rho in the GTP‐bound form and, when microinjected into cells, induced the anomalous formation of stress fibers indistinguishable from those seen in DNT‐treated cells. The results imply that the polyamine‐linked Rho, transducing signals to downstream ROCK in a novel GTP‐independent manner, plays an important role in DNT cell toxicity.