Final answer:
In the process of Non-homologous End-Joining (NHEJ), the protein complex Ku recognizes double-stranded breaks (DSB) in DNA, holding the broken ends in proximity for repair by other proteins and enzymes including DNA ligase IV.
Step-by-step explanation:
In the Non-homologous End-Joining (NHEJ) pathway for DNA repair, the protein complex that recognizes double-stranded breaks (DSB) is known as Ku. Once a DSB is identified, Ku binds to the DNA at the ends of the break, acting as a scaffolding to hold the DNA ends in proximity for further processing.
This allows end-processing proteins to trim the DNA and specialized ligases, like DNA ligase IV, to seal the ends back together, effectively repairing the break in the DNA strands.Additional proteins involved in the NHEJ pathway include the MRX (in yeast) or MRN (in mammals) complex, which binds at the DSB site and helps in recruiting other factors necessary for the repair process.
Understanding the function and interaction of these proteins is vital for comprehending how cells maintain genomic integrity in the face of DSBs that can occur from various sources including ionizing radiation, oxidative stress, and mechanical stress during cell division.