Figure 1.

TEL is covalently modified by SUMO-1. COS7 cells were transfected with HA-TEL alone (lanes 1 and 3) or with HA-TEL and Flag-SUMO-1 (lanes 2 and 4). Cell lysates (lanes 1 and 2) and the anti-Flag coimmunoprecipitation reactions (lanes 3 and 4) were subjected to Western blot analysis with anti-HA antibody. The higher molecular size band in lane 2 corresponds to SUMO-1-modified TEL, as confirmed by the coimmunoprecipitation results of lane 4. Lane 5, untransfected HEL cell lysates were separated, transferred to nylon membrane, and probed with anti-TEL antibody. Two bands were identified corresponding to unmodified and modified endogenous TEL. IP, immunoprecipitation.