In the G1 phase there are two types of DNA damage responses, the p53-dependent and the p53-independent pathways. The p53-dependent responses inhibit CDKs through the up-regulation of genes encoding CKIs mediated by the p53 protein, whereas the p53-independent mechanisms inhibit CDKs through the inhibitory T14Y15 phosphorylation of Cdk2. Failure of DNA damage checkpoints in G1 leads to mutagenic replication of damaged templates and other replication defects. Source: Reactome
Protein phosphorylation sites were added based on information from PhosphoSitePlus (R), www.phosphosite.org.
Proteins on this pathway have targeted assays available via the [CPTAC Assay Portal](https://assays.cancer.gov/available_assays?wp_id=WP45).