Fig. S7.

GK5 kinase activity is dispensable for the interaction between GK5 and SREBP-1/-2. (A) HEK293T cells were transfected with GK5-v2 or kinase-inactive GK5-v2 (D280N, D443N) and either FLAG-SREBP-1 or FLAG-SREBP-2. Cell lysates were immunoprecipitated using anti-FLAG M2 agarose and immunoblotted with antibodies against GK5 or FLAG. (B) GK5 kinase assays were carried out using immunoprecipitated SREBP-1 or SREBP-2 as substrates. Reaction mixtures were separated using Phos-tag acrylamide gel electrophoresis and immunoblotted with FLAG antibodies (Upper band, phosphorylated SREBP; Lower band, nonphosphorylated SREBP). GK5 protein expression was detected by regular SDS/PAGE and immunoblotting with MBP antibodies.