Activation of Yap-Directed Transcription by Knockdown of Conserved Cellular Functions

Abstract

The Yap-Hippo pathway has a significant role in regulating cell proliferation and growth, thus controlling organ size and regeneration. The Hippo pathway regulates two highly conserved, transcription coactivators, YAP and TAZ. The upstream regulators of the Yap-Hippo pathway have not been fully characterized. The aim of this study was to use a siRNA screen, in a liver biliary cell line, to identify regulators of the Yap-Hippo pathway that allow activation of the YAP transcription coactivator at high cell density. Activation of the YAP transcription coactivator was monitored using a high-content, image-based assay that measured the intracellular localization of native YAP protein. Active siRNAs were identified and further validated by quantification of CYR61 mRNA levels (a known YAP target gene). The effect of compounds targeting the putative gene targets identified as hits was also used for further validation. A number of validated hits reveal basic aspects of Yap-Hippo biology, such as components of the nuclear pore, by which YAP cytoplasmic-nuclear shuttling occurs, or how proteasomal degradation regulates intracellular YAP concentrations, which then alter YAP localization and transcription. Such results highlight how targeting conserved cellular functions can lead to validated activity in phenotypic assays.

Jenkins-CI, an Open-Source Continuous Integration System, as a Scientific Data and Image-Processing Platform

“…In the first example, a screen to monitor the location of a transcription factor in response to treatment by siRNAs 17 ( Suppl. Fig.…”

YAP Activation in Promoting Negative Durotaxis and Acral Melanoma Progression

“…Recent work reported a distinct amplicon of YAP on the long arm of chromosome 11 in acral melanoma [ 16 ]. YAP is a mechanical-sensitive transcriptional coactivator [ 17 ], which can be activated by stiffer substrates and stronger contraction force [ 18 , 19 ].…”