8WU8 image
Entry Detail
PDB ID:
8WU8
Keywords:
Title:
Crystal structure of the human RAD9-RAD1(F64A/M256A/F266A)-HUS1-RHINO(88-99) complex
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2023-10-20
Release Date:
2024-02-14
Method Details:
Experimental Method:
Resolution:
2.81 Å
R-Value Free:
0.26
R-Value Work:
0.21
R-Value Observed:
0.22
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Cell cycle checkpoint control protein RAD9A
Chain IDs:A
Chain Length:270
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Checkpoint protein HUS1
Chain IDs:B
Chain Length:286
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:Cell cycle checkpoint protein RAD1
Mutations:F64A, M256A, F266A
Chain IDs:C
Chain Length:282
Number of Molecules:1
Biological Source:Homo sapiens
Polymer Type:polypeptide(L)
Description:RAD9, HUS1, RAD1-interacting nuclear orphan protein 1
Chain IDs:D
Chain Length:12
Number of Molecules:1
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
Structural basis for intra- and intermolecular interactions on RAD9 subunit of 9-1-1 checkpoint clamp implies functional 9-1-1 regulation by RHINO.
J.Biol.Chem. 300 105751 105751 (2024)
PMID: 38354779 DOI: 10.1016/j.jbc.2024.105751

Abstact

Eukaryotic DNA clamp is a trimeric protein featuring a toroidal ring structure that binds DNA on the inside of the ring and multiple proteins involved in DNA transactions on the outside. Eukaryotes have two types of DNA clamps: the replication clamp PCNA and the checkpoint clamp RAD9-RAD1-HUS1 (9-1-1). 9-1-1 activates the ATR-CHK1 pathway in DNA damage checkpoint, regulating cell cycle progression. Structure of 9-1-1 consists of two moieties: a hetero-trimeric ring formed by PCNA-like domains of three subunits and an intrinsically disordered C-terminal region of the RAD9 subunit, called RAD9 C-tail. The RAD9 C-tail interacts with the 9-1-1 ring and disrupts the interaction between 9-1-1 and DNA, suggesting a negative regulatory role for this intramolecular interaction. In contrast, RHINO, a 9-1-1 binding protein, interacts with both RAD1 and RAD9 subunits, positively regulating checkpoint activation by 9-1-1. This study presents a biochemical and structural analysis of intra- and inter-molecular interactions on the 9-1-1 ring. Biochemical analysis indicates that RAD9 C-tail binds to the hydrophobic pocket on the PCNA-like domain of RAD9, implying that the pocket is involved in multiple protein-protein interactions. The crystal structure of the 9-1-1 ring in complex with a RHINO peptide reveals that RHINO binds to the hydrophobic pocket of RAD9, shedding light on the RAD9-binding motif. Additionally, the study proposes a structural model of the 9-1-1-RHINO quaternary complex. Together, these findings provide functional insights into the intra- and inter-molecular interactions on the front side of RAD9, elucidating the roles of RAD9 C-tail and RHINO in checkpoint activation.

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