Modulating Optogenetic YAP In Vitro and In Vivo.

YAP is a central regulator of the Hippo-YAP signaling axis, an evolutionarily conserved pathway that modulates organ growth and regeneration. Dysregulation of YAP signaling leads to uncontrolled proliferation, promoting epithelial-to-mesenchymal transition and invasion in cancer metastasis. Exogenous manipulation of YAP activity at the second-to-minute timescale is an important step in studying the signaling pathway. We present an optogenetic system to control the subcellular localization of YAP and therefore its activity as a transcriptional co-activator. We used the LOV2-Jα interacting domains to photocage a nuclear localization signal (NLS) attached to YAP. Under 488 nm light, the Jα helix unfolds and the interaction with LOV2 is disrupted, thereby exposing the NLS and allowing for the entire optogenetic construct to be shuttled into the nucleus. This nuclear translocation is reversible and tuneable and demonstrates functional activity after nuclear localization both in vitro and in vivo.