8WU8

Crystal structure of the human RAD9-RAD1(F64A/M256A/F266A)-HUS1-RHINO(88-99) complex

Summary for 8WU8

• Entry DOI: 10.2210/pdb8wu8/pdb
• Descriptor: Cell cycle checkpoint control protein RAD9A, Checkpoint protein HUS1, Cell cycle checkpoint protein RAD1, ... (4 entities in total)
• Functional Keywords: dna damage, checkpoint, dna repair, dna binding clamp, cell cycle
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 4
• Total formula weight: 95341.58

Authors

Hara, K.,Nagata, K.,Iida, N.,Hashimoto, H. (deposition date: 2023-10-20, release date: 2024-02-14, Last modification date: 2024-03-27)

Primary citation

Hara, K.,Tatsukawa, K.,Nagata, K.,Iida, N.,Hishiki, A.,Ohashi, E.,Hashimoto, H.
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

PubMed Abstract: 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.

PubMed: 38354779
DOI: 10.1016/j.jbc.2024.105751

Experimental method

X-RAY DIFFRACTION (2.81 Å)