Dysbindin is a potent inducer of RhoA-SRF-mediated cardiomyocyte hypertrophy.

Dysbindin is an established schizophrenia susceptibility gene thoroughly studied in the context of the brain. We have previously shown through a yeast two-hybrid screen that it is also a cardiac binding partner of the intercalated disc protein Myozap. Because Dysbindin is highly expressed in the heart, we aimed here at deciphering its cardiac function. Using a serum response factor (SRF) response element reporter-driven luciferase assay, we identified a robust activation of SRF signaling by Dysbindin overexpression that was associated with significant up-regulation of SRF gene targets, such as Acta1 and Actc1. Concurrently, we identified RhoA as a novel binding partner of Dysbindin. Further phenotypic and mechanistic characterization revealed that Dysbindin induced cardiac hypertrophy via RhoA-SRF and MEK1-ERK1 signaling pathways. In conclusion, we show a novel cardiac role of Dysbindin in the activation of RhoA-SRF and MEK1-ERK1 signaling pathways and in the induction of cardiac hypertrophy. Future in vivo studies should examine the significance of Dysbindin in cardiomyopathy.