OGFr resides in both the nucleus and the cytoplasm of the cell. Nuclear (NE) and cytoplasmic (S100) extracts were prepared from the indicated cell lines as described in the materials and methods section. The proteins (35 µg) in each extract were separated on an 8% acrylamide gel, transferred to nitrocellulose and probed with antibodies to the OGFr tandem repeat region. Addition of the OGFr tandem repeat peptide to the blot completely blocks the detection of the protein (data not shown).