A bacterial type III secretion system inhibits actin polymerization to prevent pore formation in host cell membranes
AUTOR(ES)
Viboud, Gloria I.
FONTE
Oxford University Press
RESUMO
The bacterial pathogen Yersinia pseudotuberculosis uses type III secretion machinery to translocate Yop effector proteins through host cell plasma membranes. A current model suggests that a type III translocation channel is inserted into the plasma membrane, and if Yops are not present to fill the channel, the channel will form a pore. We examined the possibility that Yops act within the host cell to prevent pore formation. Yop– mutants of Y.pseudotuberculosis were assayed for pore-forming activity in HeLa cells. A YopE– mutant exhibited high levels of pore-forming activity. The GTPase-downregulating function of YopE was required to prevent pore formation. YopE+ bacteria had increased pore-forming activity when HeLa cells expressed activated Rho GTPases. Pore formation by YopE– bacteria required actin polymerization. F-actin was concentrated at sites of contact between HeLa cells and YopE– bacteria. The data suggest that localized actin polymerization, triggered by the type III machinery, results in pore formation in cells infected with YopE– bacteria. Thus, translocated YopE inhibits actin polymerization to prevent membane damage to cells infected with wild-type bacteria.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=125656Documentos Relacionados
- NEW EMBO MEMBER’S REVIEW: Getting across—bacterial type III effector proteins on their way to the plant cell
- The mechanism of action of the Pseudomonas aeruginosa-encoded type III cytotoxin, ExoU
- Oligomerization of type III secretion proteins PopB and PopD precedes pore formation in Pseudomonas
- Type III TGF-β receptor-independent signalling of TGF-β2 via TβRII-B, an alternatively spliced TGF-β type II receptor
- Cryptosporidium parvum Infection Requires Host Cell Actin Polymerization