Fodrin CaM-binding domain cleavage by Pet from enteroaggregative Escherichia coli leads to actin cytoskeletal disruption.

摘要: We have previously shown that the plasmid-encoded toxin (Pet) of enteroaggregative Escherichia coil produces cytotoxic and enterotoxic effects. Petintoxicated epithelial cells reveal contraction cytoskeleton loss actin stress fibres. Pet effects require its internalization into cells. also degrades erythroid spectrin. delivery within intestine suggests may degrade fodrin (non-erythroid spectrin). Here we demonstrate has affinity for α-fodrin (formally named all spectrin) in vitro vivo cleaves fodrin, causing redistribution When produced cytoskeletal effects, is found intracellular aggregates as membrane blebs. recombinant GST-fodrin, generating two breakdown products 37 72 kDa. Sequencing kDa fragment demonstrated cleavage site occurred fodrin's 11th repetitive unit between M 1 9 8 V , calmodulin binding domain. Site-directed mutagenesis these amino acids prevented degradation by Pet. from cultured Pet-treated A mutant serine protease motif was unable to cause or cleave GST-fodrin. This first report showing a bacterial protease. Cleavage occurs middle domain, which leads disruption.