6u3r
From Proteopedia
Solution NMR structure of the DNAJB6b deltaST variant (Aligned on the J domain)
Structural highlights
DiseaseDNJB6_HUMAN Autosomal dominant limb-girdle muscular dystrophy type 1D. The disease is caused by mutations affecting the gene represented in this entry. There is evidence that LGMDD1 is caused by dysfunction of isoform B (PubMed:22366786).[1] FunctionDNJB6_HUMAN Plays an indispensable role in the organization of KRT8/KRT18 filaments. Acts as an endogenous molecular chaperone for neuronal proteins including huntingtin. Suppresses aggregation and toxicity of polyglutamine-containing, aggregation-prone proteins. Isoform B but not isoform A inhibits huntingtin aggregation. Has a stimulatory effect on the ATPase activity of HSP70 in a dose-dependent and time-dependent manner and hence acts as a co-chaperone of HSP70. Also reduces cellular toxicity and caspase-3 activity.[2] [3] [4] [5] [6] Publication Abstract from PubMedJ-domain chaperones are involved in the efficient handover of misfolded/partially folded proteins to Hsp70 but also function independently to protect against cell death. Due to their high flexibility, the mechanism by which they regulate the Hsp70 cycle and how specific substrate recognition is performed remains unknown. Here we focus on DNAJB6b, which has been implicated in various human diseases and represents a key player in protection against neurodegeneration and protein aggregation. Using a variant that exists mainly in a monomeric form, we report the solution structure of an Hsp40 containing not only the J and C-terminal substrate binding (CTD) domains but also the functionally important linkers. The structure reveals a highly dynamic protein in which part of the linker region masks the Hsp70 binding site. Transient interdomain interactions via regions crucial for Hsp70 binding create a closed, autoinhibited state and help retain the monomeric form of the protein. Detailed NMR analysis shows that the CTD (but not the J domain) self-associates to form an oligomer comprising approximately 35 monomeric units, revealing an intricate balance between intramolecular and intermolecular interactions. The results shed light on the mechanism of autoregulation of the Hsp70 cycle via conserved parts of the linker region and reveal the mechanism of DNAJB6b oligomerization and potentially antiaggregation. Unraveling the structure and dynamics of the human DNAJB6b chaperone by NMR reveals insights into Hsp40-mediated proteostasis.,Karamanos TK, Tugarinov V, Clore GM Proc Natl Acad Sci U S A. 2019 Oct 7. pii: 1914999116. doi:, 10.1073/pnas.1914999116. PMID:31591220[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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