Mediator of DNA Damage Checkpoint Protein 1 (MDC1) Human Recombinant Protein

The protein encoded by this gene contains an N-terminal forkhead domain, two BRCA1 C-terminal (BRCT) motifs and a central domain with 13 repetitions of an approximately 41-amino acid sequence. The encoded protein is required to activate the intra-S phase and G2/M phase cell cycle checkpoints in response to DNA damage. This nuclear protein interacts with phosphorylated histone H2AX near sites of DNA double-strand breaks through its BRCT motifs, and facilitates recruitment of the ATM kinase and meiotic recombination 11 protein complex to DNA damage foci. [provided by RefSeq, Jul 2008]

MDC1: Required for checkpoint mediated cell cycle arrest in response to DNA damage within both the S phase and G2/M phases of the cell cycle. May serve as a scaffold for the recruitment of DNA repair and signal transduction proteins to discrete foci of DNA damage marked by 'Ser-139' phosphorylation of histone H2AFX. Also required for downstream events subsequent to the recruitment of these proteins. These include phosphorylation and activation of the ATM, CHEK1 and CHEK2 kinases, and stabilization of TP53 and apoptosis. ATM and CHEK2 may also be activated independently by a parallel pathway mediated by TP53BP1. 4 isoforms of the human protein are produced by alternative splicing.

Protein type: Cell cycle regulation

Chromosomal Location of Human Ortholog: 6p21.3

Cellular Component: chromosome; focal adhesion; nucleoplasm; nucleus

Molecular Function: protein binding; protein C-terminus binding

Biological Process: cellular protein metabolic process; DNA repair; double-strand break repair; double-strand break repair via homologous recombination; double-strand break repair via nonhomologous end joining; intra-S DNA damage checkpoint; post-translational protein modification; protein sumoylation