Representative immunofluorescence staining. Amino-terminal myc epitope-tagged expression constructs were generated and expressed in HeLa cells as described previously . The scale bar represents 10 μm. (a) IκBα (U36277), a known nuclear protein, localizes to the nucleus. (b) Cyln2 (AAH53048) localizes to the cytoplasm. (c) Phf21b (AAH67021), a protein with no previous localization data, localizes to both the nucleus and cytoplasm.