Abstract 246: Acetylation of Vgll4 Regulates Hippo-yap Signaling and Postnatal Cardiac Growth

Abstract

Binding of the transcription co-activator YAP with the transcription factor TEAD stimulates growth of the heart and other organs. Many signaling pathways, including the Hippo kinase cascade, converge to regulate YAP activity. However, less in known about the mechanisms that govern TEAD. YAP overexpression potently stimulates fetal cardiomyocyte (CM) proliferation, but YAP’s mitogenic potency declines postnatally, when mammalian cardiomyocytes largely exit the cell cycle. Here, we show that VGLL4, a CM-enriched TEAD1 binding protein, inhibits CM proliferation by limiting its binding to YAP and by targeting TEAD1 for degradation. VGLL4 antagonism of TEAD1 was governed by its acetylation at K225. Overexpression of VGLL4-K225R, an acetylation-refractory mutant, enhanced TEAD1 degradation, limited neonatal CM proliferation, and caused CM necrosis and heart failure. Our study defines an acetylation-mediated, VGLL4-dependent switch that regulates YAP-TEAD1 activity and restrains CM proliferation. These insights may enable more effective regulation of TEAD-YAP activity in applications ranging from cardiac regeneration to restraining cancer.