Molecular and biological characterization of Streptococcal SpyA-mediated ADP-ribosylation of intermediate filament protein vimentin.

The Gram-positive bacterial pathogen Streptococcus pyogenes produces a C3 family ADP-ribosyltransferase designated SpyA (S. pyogenes ADP-ribosyltransferase). Our laboratory has identified a number of eukaryotic protein targets for SpyA, prominent among which are the cytoskeletal proteins actin and vimentin.

Activation of a bacterial virulence protein by the GTPase RhoA.

The Rho family of guanosine triphosphatases (GTPases) are essential eukaryotic signaling molecules that regulate cellular physiology. Virulence factors from various pathogens alter the signaling of GTPases by acting as GTPase activating factors, guanine nucleotide exchange factors, or direct covalent modifiers; however, bacterial virulence factors that sense rather than alter the signaling states of Rho GTPases have not been previously described. Here, we report that the translocated Salmonellae virulence factor SseJ binds to the guanosine triphosphate-bound form of RhoA.

Identification of SpyA, a novel ADP-ribosyltransferase of Streptococcus pyogenes.

Streptococcus pyogenes, the aetiological agent of both respiratory and skin infections, produces numerous exotoxins to establish infection. This report identifies a new exotoxin produced by this organism, termed SpyA, for S. pyogenesADP-ribosylating toxin.