Western blot analysis of extracts from 293 cells, mock transfected (-) or transfected with a construct expressing either DDK-tagged full-length human SHMT1 (hSHMT1-DDK; +) or DDK-tagged full-length human SHMT2 (hSHMT2-DDK; +), using SHMT1 Antibody (upper), DYKDDDDK Tag (9A3) Mouse mAb #8146 (middle), or GAPDH (D16H11) XP® Rabbit mAb #5174 (lower).