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Enzymatic actions of Pasteurella multocida toxin detected by monoclonal antibodies recognizing the deamidated α subunit of the heterotrimeric GTPase G q
Author(s) -
Kamitani Shigeki,
Ao Shinpei,
Toshima Hirono,
Tachibana Taro,
Hashimoto Makiko,
Kitadokoro Kengo,
FukuiMiyazaki Aya,
Abe Hiroyuki,
Horiguchi Yasuhiko
Publication year - 2011
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2011.08197.x
Subject(s) - pasteurella multocida , heterotrimeric g protein , monoclonal antibody , protein subunit , enzyme , gtpase , toxin , microbial toxins , chemistry , microbiology and biotechnology , antibody , biology , biochemistry , bacteria , g protein , receptor , immunology , gene , genetics
Pasteurella multocida toxin (PMT) is a virulence factor responsible for the pathogenesis of some Pasteurellosis . PMT exerts its toxic effects through the activation of heterotrimeric GTPase (G q , G 12/13 and G i )‐dependent pathways, by deamidating a glutamine residue in the α subunit of these GTPases. However, the enzymatic characteristics of PMT are yet to be analyzed in detail because the deamidation has only been observed in cell‐based assays. In the present study, we developed rat monoclonal antibodies, specifically recognizing the deamidated Gα q , to detect the actions of PMT by immunological techniques such as western blotting. Using the monoclonal antibodies, we found that the toxin deamidated Gα q only under reducing conditions. The C‐terminal region of PMT, C‐PMT, was more active than the full‐length PMT. The C3 domain possessing the enzyme core catalyzed the deamidation in vitro without any other domains. These results not only support previous observations on toxicity, but also provide insights into the enzymatic nature of PMT. In addition, we present several lines of evidence that Gα 11 , as well as Gα q , could be a substrate for PMT.