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DjA1 maintains Golgi integrity via interaction with GRASP65

In mammalian cells, the Golgi reassembly stacking protein of 65 kDa (GRASP65) has been implicated in both Golgi stacking and ribbon linking by forming trans-oligomers. To better understand its function and regulation, we used biochemical methods to identify the DnaJ homolog subfamily A member 1 (DjA...

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Detalles Bibliográficos
Autores principales: Li, Jie, Tang, Danming, Ireland, Stephen C., Wang, Yanzhuang
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6594443/
https://www.ncbi.nlm.nih.gov/pubmed/30566031
http://dx.doi.org/10.1091/mbc.E18-10-0613
Descripción
Sumario:In mammalian cells, the Golgi reassembly stacking protein of 65 kDa (GRASP65) has been implicated in both Golgi stacking and ribbon linking by forming trans-oligomers. To better understand its function and regulation, we used biochemical methods to identify the DnaJ homolog subfamily A member 1 (DjA1) as a novel GRASP65-binding protein. In cells, depletion of DjA1 resulted in Golgi fragmentation, short and improperly aligned cisternae, and delayed Golgi reassembly after nocodazole washout. In vitro, immunodepletion of DjA1 from interphase cytosol reduced its activity to enhance GRASP65 oligomerization and Golgi membrane fusion, while adding purified DjA1 enhanced GRASP65 oligomerization. DjA1 is a cochaperone of Heat shock cognate 71-kDa protein (Hsc70), but the activity of DjA1 in Golgi structure formation is independent of its cochaperone activity or Hsc70, rather, through DjA1-GRASP65 interaction to promote GRASP65 oligomerization. Thus, DjA1 interacts with GRASP65 to enhance Golgi structure formation through the promotion of GRASP65 trans-oligomerization.