Cytoplasmic p44 is essential for growth of prostate epithelial cells.

<p>(A) Expression of p44, NES-p44, or NLS-p44 in the <i>p44-null</i> prostate epithelial cells. Western blot analysis of whole cell lysates (10 µg) made from <i>p44-null</i> prostate epithelial cells infected with control lentivirus (lane 1) or lentivirus expressing p44 (lane 2), NES-p44 (lane 3), or NLS-p44 (lane 4), as indicated. The p44 wild-type (<i>p^44loxP/loxp</i>) epithelial cells infected with control lentivirus were used as the control (lane 5). (B) The subcellular localization of p44, NES-p44, and NLS-p44 in prostate epithelial cells. Immunostaining of p44 in p44 wild-type (<i>p^44loxP/loxp</i>) epithelial cells (top panels), in <i>p44-null</i> prostate epithelial cells infected with control lentivirus (2^nd panel) or lentivirus expressing p44 (3^rd panel), NES-p44 (4^th panel), or NLS-p44 (bottom panel), as indicated. P44 and the nucleus were stained in red and green, respectively. The left pictures are a merger of p44 and nuclear staining. (C) Cytoplasmic p44 fully restored growth arrest of prostate epithelial cells induced by loss of p44. Growth curves of <i>p44-null</i> prostate epithelial cells infected with control lentivirus or lentivirus expressing p44, NES-p44, or NLS-p44. One-way ANOVA analysis: F = 43.00, p<0.0001, R square = 0.9485. The p value of unpaired Student’s t-Test of data between p44^loxP/loxP and NES-p44, p44, or p44^−/− epithelial cells are 0.3352, 0.2873, or 0.0003.