Yes-Associated Protein (YAP) Promotes the Nuclear Import of p73

Abstract

p73 has been identified as a structural and functional homolog of the tumor suppressor p53. However, mechanisms that regulate the localization of p73 have not been fully clarified. The Yes-associated protein (YAP) is a transcriptional coactivator. As a transcriptional coactivator, YAP needs to bind transcription factors to stimulate gene expression. p73 is a reported YAP target transcription factors and YAP has been shown to positively regulate p73 in promoting apoptosis. Previous studies show that p73 interacts with YAP through its PPPY motif, and increases p73 transactivation of apoptotic genes. In this study, we focused on YAP's regulation of the localization of p73. After transient transfection into Rat pheochromocytoma (PC12) cells and Human embryonic kidney 293T cells with GFP-YAP and/or YFP-p73, and incubated for 24 hours expression. p73 was fused to YFP to allow the examination of its subcellular localization. When expressed alone, YFP-p73 was distributed throughout the cell. When coexpressed with YAP, nuclear accumulation of YFP-p73 became evident. We quantitated the effect of YAP on the redistribution of YFP-p73 by counting cells with nuclear-only YFP signal. We found that YAP can influence the subcellular distribution of p73. Altogether, coexpression with YAP affected the subcellular distribution of the p73 protein. Our studies attribute a central role to YAP in regulating p73 accumulation and YAP, at least in part, might promote the nuclear import of p73.