Fig. 2. Hsp72 does not affect SEK1 or MEKK1 activity in NIH 3T3 cells. NIH 3T3-Hsp72 and NIH 3T3-neo cells were exposed to UV light (60 J/m²) and then incubated further at 37°C for 1 h. Cell lysates were subjected to immunoprecipitation with either anti-SEK1 or anti-MEKK1 antibody. Immunopellets were assayed for SEK1 or MEKK1 activity using GST–SAPKβ(K55R) or GST–SEK1(K129R) as substrate, respectively. IB, immunoblot.