title: Gln 63 of Rho is deamidated by Escherichia coli cytotoxic necrotizing factor-1.
abstract: The actin cytoskeleton is regulated by GTP-hydrolysing proteins, the Rho GTPases, which act as molecular switches in diverse signal-transduction processes. Various bacterial toxins can inactivate Rho GTPases by ADP-ribosylation or glucosylation. Previous research has identified Rho proteins as putative targets for Escherichia coli cytotoxic necrotizing factors 1 and 2 (CNF1 and 2). These toxins induce actin assembly and multinucleation in culture cells. Here we show that treatment of RhoA with CNF1 inhibits the intrinsic GTPase activity of RhoA and completely blocks GTPase activity stimulated by the Rho-GTPase-activating protein (rhoGAP). Analysis by mass spectrometry and amino-acid sequencing of proteolytic peptides derived from CNF1-treated RhoA indicate that CNF1 induces deamidation of a glutamine residue at position 63 (Gln 63) to give constitutively active Rho protein.
authors.affiliation: Institut für Pharmakologie und Toxikologie der Albert-Ludwigs-Universität Freiburg, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Schmidt
authors.forename: P
authors.initials: P
authors.lastname: Sehr
authors.forename: M
authors.initials: M
authors.lastname: Wilm
authors.forename: J
authors.initials: J
authors.lastname: Selzer
authors.forename: M
authors.initials: M
authors.lastname: Mann
authors.forename: K
authors.initials: K
authors.lastname: Aktories
mesh_terms: D016475:3T3 Cells; D000199:Actins / Q000378:metabolism; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001427:Bacterial Toxins / Q000378:metabolism / Q000494:pharmacology*; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D003603:Cytotoxins / Q000378:metabolism / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D020558:GTP Phosphohydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D020690:GTPase-Activating Proteins; D005973:Glutamine / Q000378:metabolism*; D006031:Glycosylation; D006160:Guanosine Triphosphate / Q000378:metabolism; D013058:Mass Spectrometry; D051379:Mice; D008845:Microinjections; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D062367:ortho-Aminobenzoates / Q000378:metabolism; D020742:rhoA GTP-Binding Protein
chemical_list: D000199:Actins; D001427:Bacterial Toxins; D003603:Cytotoxins; D029968:Escherichia coli Proteins; D020690:GTPase-Activating Proteins; D011993:Recombinant Fusion Proteins; D062367:ortho-Aminobenzoates; C085379:rho GTPase-activating protein; D005973:Glutamine; C060296:cytotoxic necrotizing factor type 1; D000246:Adenosine Diphosphate Ribose; C063981:2'(3')-O-(N-methyl)anthraniloylguanosine 5'-triphosphate; D006160:Guanosine Triphosphate; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein