HrpI of Erwinia amylovora functions in secretion of harpin and is a member of a new protein family.
AUTOR(ES)
Wei, Z M
RESUMO
HrpI, a 78-kDa protein, functions in the secretion of harpin, a proteinaceous elicitor of the hypersensitive response from Erwinia amylovora. The predicted amino acid sequence of HrpI is remarkably similar to that of LcrD of Yersinia species, the first member of a recently described protein family. Other proteins of the family are MixA from Shigella flexneri, InvA from Salmonella typhimurium, FlhA from Caulobacter crescentus, HrpI from Pseudomonas syringae pv. syringae, HrpO from Pseudomonas solanacearum, and HrpC2 from Xanthomonas campestris pv. vesicatoria. Cells of E. amylovora containing mutated hrpI genes or cells of Escherichia coli containing the cloned hrp gene cluster with mutated hrpI produce but do not export harpin. When similar cells with functional hrpI genes were grown at 25 degrees C, but not at 37 degrees C, harpin was exported to the culture supernatant. Direct evidence that HrpI is involved in the secretion of a virulence protein has been offered. Two other loci of the hrp gene cluster are involved in the regulation of harpin, and four other loci also are involved in the secretion of harpin. Since harpin and other proteins likely to be secreted by the LcrD family of proteins lack typical signal peptides, their secretion mechanism is distinct from the general protein export pathway.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=206975Documentos Relacionados
- hrpL activates Erwinia amylovora hrp gene transcription and is a member of the ECF subfamily of sigma factors.
- The hrpA and hrpC operons of Erwinia amylovora encode components of a type III pathway that secretes harpin.
- HrpW of Erwinia amylovora, a New Harpin That Contains a Domain Homologous to Pectate Lyases of a Distinct Class
- Pectate lyase PelI of Erwinia chrysanthemi 3937 belongs to a new family.
- Rapid and Transient Activation of a Myelin Basic Protein Kinase in Tobacco Leaves Treated with Harpin from Erwinia amylovora.