STEAP3 was downregulated in response to hypertrophic stimuli and deletion of STEAP3 exacerbated cardiac hypertrophy in response to TAC whereas STEAP3 overexpression suppressed MEK/ERK signaling and cardiomyocyte hypertrophy that was circumvented by overexpression of constitutively-active Rac1G12V [54], suggesting STEAP3 may antagonize pathologic cardiomyocyte hypertrophy through repression of Rac1. The gene discussed is MAPK1; the disease is cardiac hypertrophy.