ausblenden:
Schlagwörter:
Carrier Proteins/genetics/*metabolism
Molecular Chaperones/metabolism
Mutation
Protein Binding
Protein Transport
Saccharomyces cerevisiae/*metabolism
Saccharomyces cerevisiae Proteins/genetics/*metabolism
Signal Transduction
Ubiquitin/genetics/*metabolism
Zusammenfassung:
Abstract TPR proteins modulate the activity of molecular chaperones. Here, we describe the S. cerevisiae TPR protein Sgt2 as interaction partner of Ssa1 and Hsp104 and as a component of the GET pathway by interacting with Get5. The GET pathway mediates the sorting of tail-anchored (TA) proteins, harboring a C-terminal trans-membrane segment, to the ER membrane. S. cerevisiae sgt2Delta cells show partial defects in TA protein sorting. Sgt2 activity in vivo relies on its N- and C-terminal domains, whereas the central TPR domain and thus chaperone interactions are dispensable. We show that TA protein sorting defects are more severe in sgt2Delta get5Delta mutants compared to single knockouts. Furthermore, overproduction of Sgt2 becomes toxic to get3Delta but not to get5Delta cells. Together, these findings indicate an additional, Get5-independent role of Sgt2 in TA protein sorting, pointing to parallel pathways of substrate delivery to Get3.
