6zyj

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Crystal structure of Hsc70 ATPase domain in complex with ADP and calciumCrystal structure of Hsc70 ATPase domain in complex with ADP and calcium

Structural highlights

6zyj is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.85Å
Ligands:, , ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

HSP7C_HUMAN Acts as a repressor of transcriptional activation. Inhibits the transcriptional coactivator activity of CITED1 on Smad-mediated transcription. Chaperone. Component of the PRP19-CDC5L complex that forms an integral part of the spliceosome and is required for activating pre-mRNA splicing. May have a scaffolding role in the spliceosome assembly as it contacts all other components of the core complex.[1]

Publication Abstract from PubMed

The metazoan endoplasmic reticulum (ER) serves both as a hub for maturation of secreted proteins and as an intracellular calcium storage compartment, facilitating calcium release-dependent cellular processes. ER calcium depletion robustly activates the unfolded protein response (UPR). However, it is unclear how fluctuations in ER calcium impact organellar proteostasis. Here we report that calcium selectively affects the dynamics of the abundant metazoan ER Hsp70 chaperone BiP, by enhancing its affinity for ADP. In the calcium-replete ER, ADP rebinding to post-ATP hydrolysis BiP-substrate complexes competes with ATP binding during both spontaneous and co-chaperone-assisted nucleotide exchange, favouring substrate retention. Conversely, in the calcium-depleted ER, relative acceleration of ADP-to-ATP exchange favours substrate release. These findings explain the rapid dissociation of certain substrates from BiP observed in the calcium-depleted ER and suggest a mechanism for tuning ER quality control and coupling UPR activity to signals that mobilise ER calcium in secretory cells.

Calcium depletion challenges endoplasmic reticulum proteostasis by destabilising BiP-substrate complexes.,Preissler S, Rato C, Yan Y, Perera LA, Czako A, Ron D Elife. 2020 Dec 9;9. pii: 62601. doi: 10.7554/eLife.62601. PMID:33295873[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Yahata T, de Caestecker MP, Lechleider RJ, Andriole S, Roberts AB, Isselbacher KJ, Shioda T. The MSG1 non-DNA-binding transactivator binds to the p300/CBP coactivators, enhancing their functional link to the Smad transcription factors. J Biol Chem. 2000 Mar 24;275(12):8825-34. PMID:10722728
  2. Preissler S, Rato C, Yan Y, Perera LA, Czako A, Ron D. Calcium depletion challenges endoplasmic reticulum proteostasis by destabilising BiP-substrate complexes. Elife. 2020 Dec 9;9:e62601. PMID:33295873 doi:10.7554/eLife.62601

6zyj, resolution 1.85Å

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OCA