REDK is predominantly a nuclear protein.

(A) UT7-EPO cells were in log phase (L) or starved for EPO (S) for 2 days. Crude cytoplasmic (CPX) and nuclear protein (NPX) extracts were prepared, and proportionate amounts of cytoplasmic and nuclear protein were transferred to nitrocellulose. The Western was probed with REDK-specific sera and detected by ECL. (B) REDK was immunoprecipitated from companion cytoplasmic and nuclear protein extracts with affinity-purified antisera for REDK and reacted after the addition of ³³P-ATP. Products were denatured, electrophoresed, and exposed for imaging. Normalized volumes of protein extracts were loaded so that each lane contained immunoprecipitates from the same number of cells.