The KEEP ON GOING protein of Arabidopsis regulates intracellular protein trafficking and is degraded during fungal infection.
Plant Cell
; 24(11): 4717-30, 2012 Nov.
Article
em En
| MEDLINE
| ID: mdl-23192225
ABSTRACT
In plants, the trans-Golgi network and early endosomes (TGN/EE) function as the central junction for major endomembrane trafficking events, including endocytosis and secretion. Here, we demonstrate that the KEEP ON GOING (KEG) protein of Arabidopsis thaliana localizes to the TGN/EE and plays an essential role in multiple intracellular trafficking processes. Loss-of-function keg mutants exhibited severe defects in cell expansion, which correlated with defects in vacuole morphology. Confocal microscopy revealed that KEG is required for targeting of plasma membrane proteins to the vacuole. This targeting process appeared to be blocked at the step of multivesicular body (MVB) fusion with the vacuolar membrane as the MVB-associated small GTPase ARA6 was also blocked in vacuolar delivery. In addition, loss of KEG function blocked secretion of apoplastic defense proteins, indicating that KEG plays a role in plant immunity. Significantly, KEG was degraded specifically in cells infected by the fungus Golovinomyces cichoracearum, suggesting that this pathogen may target KEG to manipulate the host secretory system as a virulence strategy. Taking these results together, we conclude that KEG is a key component of TGN/EE that regulates multiple post-Golgi trafficking events in plants, including vacuole biogenesis, targeting of membrane-associated proteins to the vacuole, and secretion of apoplastic proteins.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Doenças das Plantas
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Arabidopsis
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Proteínas de Arabidopsis
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Ubiquitina-Proteína Ligases
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article