Fig. 1

a Overexpression of Wt TLK1B and Mut TLK1B in stably transfected HEK293 cells. b TLK1B Wt and Mut cells or empty vector controls (EV) were treated for 2 h with doxo to promote the Chk1-dpendent phosphorylation of TLK1B (S457). TLK1B S457 phospho specific antibody recognizes only the overexpressed Wt TLK1B and not the Mut TLK1B. Note that the p-TLK1B band seen in the Mut lane corresponds to the endogenous TLK1B and not the transfected TLK1B Mut. c The basal phosphorylation of Rad9 (S328) is enhanced in cells expressing Mut TLK1B with respect to EV or cells expressing Wt TLK1B. d The phosphorylation of Rad9 (S328) persists in damage resistant Mut TLK1B expressing cells treated with doxo. e Pattern of Rad9 (S328) phosphorylation after recovery from HU in the cells expressing Mut TLK1B or Wt TLK1B. Note that TLK1B overexpression is unaffected by HU treatment in these cells