title: Clostridium botulinum C3 ADP-ribosyltransferase.
abstract: C3 and C3-like ADP-ribosyltransferases modify the low-molecular-mass GTP-binding proteins Rho and Rac. ADP-ribosylation occurs in asparagine-41, which is located in the putative effector region of these highly conserved regulatory proteins. First studies indicate that the Rho proteins are somehow involved in the regulation of cytoskeletal proteins, e.g., microfilament proteins. Although the precise mechanism of the interaction of the C3 substrate with cytoskeletal elements is unclear, it appears that the ADP-ribosylation by C3 renders the GTP-binding protein biologically inactive. Thus C3 and/or C3-like ADP-ribosyltransferases may be useful instruments with which to study the physiological functions of its eukaryotic substrates. Moreover, those studies may help to elucidate whether these exoenzymes are of pathophysiological and pathogenetic relevance in diseases caused by clostridia producing these agents.
authors.affiliation: Institut für Pharmakologie und Toxikologie, Universität des Saarlandes, Homburg, FRG.
authors.forename: K
authors.initials: K
authors.lastname: Aktories
authors.forename: C
authors.initials: C
authors.lastname: Mohr
authors.forename: G
authors.initials: G
authors.lastname: Koch
mesh_terms: D036002:ADP Ribose Transferases / Q000378:metabolism*; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000595:Amino Acid Sequence; D000828:Animal Population Groups / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001905:Botulinum Toxins / Q000378:metabolism*; D003014:Clostridium botulinum / Q000201:enzymology*; D005057:Eukaryotic Cells / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D015290:Second Messenger Systems / Q000187:drug effects; D012689:Sequence Homology, Nucleic Acid; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D020743:rhoB GTP-Binding Protein
chemical_list: D005656:Fungal Proteins; D008565:Membrane Proteins; D000246:Adenosine Diphosphate Ribose; D006160:Guanosine Triphosphate; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D001905:Botulinum Toxins; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D020743:rhoB GTP-Binding Protein