Solution structure of the Rpn1 T1 site with the Rad23 UBL domainSolution structure of the Rpn1 T1 site with the Rad23 UBL domain

Structural highlights

2nbw is a 2 chain structure with sequence from Baker's yeast. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
Gene:RPN1, HRD2, NAS1, RPD1, YHR027C (Baker's yeast), RAD23, YEL037C, SYGP-ORF29 (Baker's yeast)
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[RPN1_YEAST] Acts as a regulatory subunit of the 26S proteasome which is involved in the ATP-dependent degradation of ubiquitinated proteins.[1] [RAD23_YEAST] Plays a central role both in proteasomal degradation of misfolded proteins and DNA repair. Central component of a complex required to couple deglycosylation and proteasome-mediated degradation of misfolded proteins in the endoplasmic reticulum that are retrotranslocated in the cytosol. Involved in DNA excision repair. May play a part in DNA damage recognition and/or in altering chromatin structure to allow access by damage-processing enzymes.

Publication Abstract from PubMed

Three receptors (Rpn1/S2/PSMD2, Rpn10/S5a, Rpn13/Adrm1) in the proteasome bind substrates by interacting with conjugated ubiquitin chains and/or shuttle factors (Rad23/HR23, Dsk2/PLIC/ubiquilin, Ddi1) that carry ubiquitinated substrates to proteasomes. We solved the structure of two such receptors with their preferred shuttle factor, namely hRpn13Pru:hPLIC2UBL and scRpn1 T1:scRad23UBL. We find that ubiquitin folds in Rad23 and Dsk2 are fine-tuned by residue substitutions to achieve high affinity for Rpn1 and Rpn13, respectively. A single substitution in hPLIC2 yields enhanced interactions with the Rpn13 ubiquitin contact surface and sterically blocks hRpn13 binding to its preferred ubiquitin chain type, K48-linked chains. Rpn1 T1 binds two ubiquitins in tandem and we find that Rad23 binds exclusively to the higher-affinity Helix28/Helix30 site. Rad23 contacts at Helix28/Helix30 are optimized compared to ubiquitin by multiple conservative amino acid substitutions. Thus, shuttle factors deliver substrates to proteasomes through fine-tuned ubiquitin-like surfaces.

Structures of Rpn1 T1:Rad23 and hRpn13:hPLIC2 Reveal Distinct Binding Mechanisms between Substrate Receptors and Shuttle Factors of the Proteasome.,Chen X, Randles L, Shi K, Tarasov SG, Aihara H, Walters KJ Structure. 2016 Jul 6. pii: S0969-2126(16)30125-3. doi:, 10.1016/j.str.2016.05.018. PMID:27396824[2]

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

See Also

References

  1. Glickman MH, Rubin DM, Fried VA, Finley D. The regulatory particle of the Saccharomyces cerevisiae proteasome. Mol Cell Biol. 1998 Jun;18(6):3149-62. PMID:9584156
  2. Chen X, Randles L, Shi K, Tarasov SG, Aihara H, Walters KJ. Structures of Rpn1 T1:Rad23 and hRpn13:hPLIC2 Reveal Distinct Binding Mechanisms between Substrate Receptors and Shuttle Factors of the Proteasome. Structure. 2016 Jul 6. pii: S0969-2126(16)30125-3. doi:, 10.1016/j.str.2016.05.018. PMID:27396824 doi:http://dx.doi.org/10.1016/j.str.2016.05.018
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