CK2 associates with NF-κB in MM cells. (A-C) Confocal immunofluorescence microscopy of CK2 (Texas red), NF-κB p65/RelA (green, Alexa 488), and merge showing scant colocalization (white arrows) of the 2 proteins in the cytoplasm in OPM2 cells. (D-F) Confocal immunofluorescence microscopy of CK2 (green, Alexa 488), NF-κB p50/105 (Texas red), and merge showing abundant colocalization (white arrows) of the 2 proteins in the nucleus in OPM2 cells (600× magnification, oil, top panels, 1000× magnification, oil, bottom panels). (G) Association of endogenous CK2α and NF-κB p50/105 in MM cells. Coimmunoprecipitation of endogenous CK2α and NF-κB p50/105 in OPM2 MM cells. Cell lysates were immunoprecipitated with a preimmune rabbit serum (lane 1) or with an antibody recognizing p50/105 (lane 2) and then immunoblotted for CK2α (top) and NF-κB p50/105 (bottom). Input loading is shown in lane 3.