SBDS is not required for NPM protein stability or nucleolar localization. (A) Primary fibroblast lysates from healthy controls or SDS patients (DF259, DF250, CH126, CH128) were immunoblotted for SBDS and NPM. (B) HeLa cells were transfected with siRNA against either luciferase (Luc) or NPM. Cells were lysed 72 hours after transfection and immunoblotted for SBDS, NPM, and tubulin. (C) Normal control and DF259 primary fibroblasts were fixed and stained for SBDS (green) and NPM (red) and counterstained with DAPI (blue) to visualize the nuclei. (D) HeLa cells were transfected with siRNA against either luciferase (++ si Luc) or NPM (+ si NPM) for 48 hours. Cells were fixed and stained for SBDS (green) and NPM (red) and counterstained with DAPI (blue). See “Patients, materials, and methods; Immunofluorescence” for image acquisition details.