Abstract 13368: Acetylation of VGLL4 Tdu Domain Modulates Its Activity to Regulate Postnatal Cardiac Growth (Best of Basic Science Abstract)

Abstract

Mammalian cardiomyocytes (CM) largely exit the cell cycle shortly after birth, limiting the heart’s capacity to recover from injury. The mechanisms that enforce neonatal CM cell cycle withdrawal are largely unknown. CM proliferation is stimulated by interaction of the co-activator YAP, the terminal effector of Hippo signaling, with the transcription factor TEAD1, but YAP’s mitogenic potency declines in the adult compared to fetal or newborn heart. Here we show that VGLL4, a CM-enriched TEAD1 binding protein, inhibits CM proliferation by competing with YAP for TEAD1 binding. Moreover, VGLL4 activity is regulated by acetylation of the lysine 225 (K225) residing in its first Tondu (Tdu) domain. Acetylation at K225 antagonized its interaction with TEAD1 in the neonatal heart. Overexpression of VGLL4 with a point mutation that blocks its acetylation enhanced VGLL4-TEAD1 interaction and limited CM proliferation, resulting in lethal cardiac hypoplasia. Our study defines a novel acetylation-mediated, VGLL4-dependent switch that regulates Hippo-YAP signaling and that restrains CM proliferation. These insights may enable more effective approaches to cardiac regeneration.