(center map)
(1) CHEK2@nucleus - ATM_Ser 1981_pho:NBS1__pho@nucleus -> CHEK2_Thr68_pho@nucleus
(2) p53*@nucleus - CHEK2_Thr68_pho@nucleus - ATR@nucleus - ATM_Ser 1981_pho:NBS1__pho@nucleus -> p53*_Ser15_pho@nucleus
(3) ATM_Ser 1981_pho@nucleus+NBS1__pho@nucleus -> ATM_Ser 1981_pho:NBS1__pho@nucleus