A repair factor 53BP1 . Accumulation of EXPAND1/MUM1 at damaged DNA sites is thought to modify the structure of the chromatin and allow access to other DNA repair factors . 53BP1 activates the checkpoint kinase ATM and promotes DNA double strand break repair via nonhomologous end joining (NHEJ) repair pathway .蛋白別名為:melanoma associated antigen (mutated) 1;基因ID為:84939;蛋白質ID:Q2TAK8