Distribution of the SELMA translocon in secondary plastids of red algal origin and predicted uncoupling of ubiquitin-dependent translocation from degradation.
Eukaryot Cell
; 11(12): 1472-81, 2012 Dec.
Article
em En
| MEDLINE
| ID: mdl-23042132
ABSTRACT
Protein import into complex plastids of red algal origin is a multistep process including translocons of different evolutionary origins. The symbiont-derived ERAD-like machinery (SELMA), shown to be of red algal origin, is proposed to be the transport system for preprotein import across the periplastidal membrane of heterokontophytes, haptophytes, cryptophytes, and apicomplexans. In contrast to the canonical endoplasmic reticulum-associated degradation (ERAD) system, SELMA translocation is suggested to be uncoupled from proteasomal degradation. We investigated the distribution of known and newly identified SELMA components in organisms with complex plastids of red algal origin by intensive data mining, thereby defining a set of core components present in all examined organisms. These include putative pore-forming components, a ubiquitylation machinery, as well as a Cdc48 complex. Furthermore, the set of known 20S proteasomal components in the periplastidal compartment (PPC) of diatoms was expanded. These newly identified putative SELMA components, as well as proteasomal subunits, were in vivo localized as PPC proteins in the diatom Phaeodactylum tricornutum. The presented data allow us to speculate about the specific features of SELMA translocation in contrast to the canonical ERAD system, especially the uncoupling of translocation from degradation.
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1
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
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Diatomáceas
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Plastídeos
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Ubiquitina
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Complexo de Endopeptidases do Proteassoma
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Rodófitas
Tipo de estudo:
Prognostic_studies
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Risk_factors_studies
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article