RESEARCH ARTICLE YAP Regulates S-Phase Entry in Endothelial

The Hippo pathway regulates cell proliferation and apoptosis through the Yes-associated protein (YAP) transcriptional activator. YAP has a well-described role in promoting cell pro-liferation and survival, but the precise mechanisms and transcriptional targets that underlie these properties are still unclear and likely context-dependent. We found, using siRNA-mediated knockdown, that YAP is required for proliferation in endothelial cells but not HeLa cells. Specifically, YAP is required for S-phase entry and its absence causes cells to accu-mulate in G1. Microarray analysis suggests that YAP mediates this effect by regulating the transcription of genes involved in the assembly and/or firing of replication origins and homol-ogous recombination of DNA. These findings thus provide insight into the molecular mecha-nisms by which YAP regulates cell cycle progression