PBX1 and non-small cell lung carcinoma: Given K48- and K63-linked ubiquitination are two typical ubiquitination forms, we co-transfected HEK293T cells with TRIM26 and K48-, K48R-, K63- and K63R-Ub plasmids, respectively, the subsequent IP/IB assays showed that PBX1 was heavily ubiquitinated only in the presence of K48- and K63R-Ub but not K48R- and K63-Ub, suggesting that TRIM26 might mediate PBX1 ubiquitination in a K48- but not K63-linked manner (Fig. 3D), which was further verified in NSCLC cells by a K48-Ub and a K63-Ub specific antibody (Fig. 3E, F and G).