Bag6 (BCL2-associated athanogene cochaperone 6) is part of a cytosolic protein quality control complex involved in the post- translational delivery of tail-anchored/type II transmembrane proteins to the endoplasmic reticulum membrane, in the mislocalised protein degradation pathway and in the endoplasmic reticulum- associated degradation. The BAG-similar domain, found at the C- terminal end of this protein plays a role in the interaction with the other members of the complex, Ubl4A and TRC35. This domain shows three helices in an extended conformation that differ from the three-helix bundle fold of the canonical BAG domain (Pfam:PF02179) [1,2].

1: Bag6 complex contains a minimal tail-anchor-targeting module and a mock BAG domain. Mock JY, Chartron JW, Zaslaver M, Xu Y, Ye Y, Clemons WM Jr; Proc Natl Acad Sci U S A. 2015;112:106-111. PMID:25535373

2: Structure of a BAG6 (Bcl-2-associated athanogene 6)-Ubl4a (ubiquitin-like protein 4a) complex reveals a novel binding interface that functions in tail-anchored protein biogenesis. Kuwabara N, Minami R, Yokota N, Matsumoto H, Senda T, Kawahara H, Kato R; J Biol Chem. 2015;290:9387-9398. PMID:25713138