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Functional insights into the Shigella type III needle tip IpaD in secretion control and cell contact.
Schiavolin, Lionel; Meghraoui, Alaeddine; Cherradi, Youness; Biskri, Latéfa; Botteaux, Anne; Allaoui, Abdelmounaaïm.
Afiliação
  • Schiavolin L; Laboratoire de Bactériologie Moléculaire, Faculté de Médecine, Université Libre de Bruxelles, Route de Lennik, 808, 1070 Bruxelles, Belgium.
Mol Microbiol ; 88(2): 268-82, 2013 Apr.
Article em En | MEDLINE | ID: mdl-23421804
ABSTRACT
Type III secretion apparatus (T3SA) are complex nanomachines that insert a translocation pore into the host cell membrane through which effector proteins are injected into the cytosol. In Shigella, the pore is inserted by a needle tip complex that also controls secretion. IpaD is the key protein that rules the composition of the tip complex before and upon cell contact or Congo red (CR) induction. However, how IpaD is involved in secretion control and translocon insertion remains not fully understood. Here, we report the phenotypic analysis of 20 10-amino acids deletion variants all along the coiled-coil and the central domains of IpaD (residues 131-332). Our results highlight three classes of T3S phenotype; (i) wild-type secretion, (ii) constitutive secretion of all classes of effectors, and (iii) constitutive secretion of translocators and early effectors, but not of late effectors. Our data also suggest that the composition of the tip complex defines both the T3SA inducibility state and late effectors secretion. Finally, we shed light on a new aspect regarding the contact of the needle tip with cell membrane by uncoupling the Shigella abilities to escape macrophage vacuole, and to insert the translocation pore or to invade non-phagocytic cells.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Proteínas de Bactérias / Regulação Bacteriana da Expressão Gênica / Membrana Celular / Eritrócitos / Sistemas de Secreção Bacterianos / Macrófagos / Antígenos de Bactérias Limite: Animals / Humans Idioma: En Ano de publicação: 2013 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Proteínas de Bactérias / Regulação Bacteriana da Expressão Gênica / Membrana Celular / Eritrócitos / Sistemas de Secreção Bacterianos / Macrófagos / Antígenos de Bactérias Limite: Animals / Humans Idioma: En Ano de publicação: 2013 Tipo de documento: Article