title: Cooperative and independent activities of Sgt2 and Get5 in the targeting of tail-anchored proteins.
abstract: 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 sgt2Δ 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 sgt2Δ get5Δ mutants compared to single knockouts. Furthermore, overproduction of Sgt2 becomes toxic to get3Δ but not to get5Δ 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.
authors: Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany.
authors: Christian
authors: C
authors: Kohl
authors: Peter
authors: P
authors: Tessarz
authors: Karina
authors: K
authors: von der Malsburg
authors: Regina
authors: R
authors: Zahn
authors: Bernd
authors: B
authors: Bukau
authors: Axel
authors: A
authors: Mogk