InterPro domain: IPR007150

This entry consists of the human Hus1 protein and budding yeast Mec3. They are components of the checkpoint clamp complex involved in the surveillance mechanism that allows the DNA repair pathways to act to restore the integrity of the DNA prior to DNA synthesis or separation of the replicated chromosomes [ 1 , 2 ].

Hus1, Rad1, and Rad9 (which share homology with Mec1, Rad17, Ddc1 in budding yeast) are three evolutionarily conserved proteins required for checkpoint control. These proteins are known to form a stable complex. Structurally, the Ddc1-Mec3-Rad17 complex is similar to the PCNA complex, which forms trimeric ring-shaped clamps. Ddc1-Mec3-Rad17 plays a role in checkpoint activation that permits DNA-repair pathways to prevent cell cycle progression in response to DNA damage and replication stress [ 3 , 4 ].

1. Role of a complex containing Rad17, Mec3, and Ddc1 in the yeast DNA damage checkpoint pathway. Mol. Cell. Biol. 19, 1136-43
2. Molecular analysis of hus1+, a fission yeast gene required for S-M and DNA damage checkpoints. Mol. Gen. Genet. 254, 389-99
3. The novel DNA damage checkpoint protein ddc1p is phosphorylated periodically during the cell cycle and in response to DNA damage in budding yeast. EMBO J. 16, 5216-26
4. 9-1-1: PCNA's specialized cousin. Trends Biochem. Sci. 36, 563-8