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Characterization of Aspergillus nidulans DidB(Did2), a non-essential component of the multivesicular body pathway

ESCRT-III heteropolymers mediate membrane protein cargo sorting into multivesicular endosomes for subsequent vacuolar degradation. We studied the localization of largely uncharacterized Aspergillus nidulans ESCRT-III using its key structural component Vps32 and the ‘associated’ component DidB(Did2)....

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Detalles Bibliográficos
Autores principales: Hervás-Aguilar, América, Rodríguez-Galán, Olga, Galindo, Antonio, Abenza, Juan F., Arst, Herbert N., Peñalva, Miguel A.
Formato: Texto
Lenguaje:English
Publicado: Academic Press 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884189/
https://www.ncbi.nlm.nih.gov/pubmed/20362686
http://dx.doi.org/10.1016/j.fgb.2010.03.010
Descripción
Sumario:ESCRT-III heteropolymers mediate membrane protein cargo sorting into multivesicular endosomes for subsequent vacuolar degradation. We studied the localization of largely uncharacterized Aspergillus nidulans ESCRT-III using its key structural component Vps32 and the ‘associated’ component DidB(Did2). Vps32-GFP localizes to motile early endosomes as reported, but predominates in aggregates often associated with vacuoles due to inability to dissociate from endosomes. DidB(Did)(2) regulating Vps4 (the ATPase disassembling ESCRT-III) is not essential. Consistent with this accessory role, didBΔ is unable to block the MVB sorting of the glutamate transporter AgtA, but increases its steady-state level and mislocalizes a fraction of the permease to the plasma membrane under conditions promoting its vacuolar targeting. didBΔ exacerbates the dominant-negative growth defect resulting from Vps32-GFP over-expression. A proportion of DidB-GFP is detectable in early endosomes colocalizing with RabA(Rab5) and accumulating in nudA1 tips, suggesting that ESCRT-III assembles on endosomes from the early steps of the endocytic pathway.