Two regions of <i>Php4</i> encompassing amino acid residues 171 to 174 and 234 to 240 are involved in targeting <i>Php4</i> to the nucleus.

<p><i>A</i>, Schematic illustration of wild-type (WT) and mutant versions (N1 to N7) of GFP-Php4 fusion protein. Green, red and blue boxes represent GFP coding sequence, NES, and putative NLS, respectively. Black boxes (marked with an asterisk) indicate mutated NLS. The amino acid residues of Php4 are numbered relative to its initiator codon. <i>B</i>, Fluorescence microscopy was used to visualize cellular location of GFP-Php4 and its mutant derivatives that were expressed in <i>php4Δ</i> cells. When indicated, cultures were treated with Dip (250 μM) or FeCl₃ (Fe) (100 μM) for 3 h. Cells were stained using Hoechst to visualize nuclear DNA, whereas Nomarski optics was used to monitor cell morphology. The results shown are representative of five independent experiments.