SMAD2 and chronic kidney disease: When CKD cells were treated with TGFβ, SMAD2 was phosphorylated (Fig. 2B, lane 2 vs. lane 4) and SMAD4 was translocated into the nucleus (Fig. 2C, lane 2 vs. lane 4) even in the absence of CK2 activation (Fig. 2B, lane 2 vs. lane 4).