Transcriptional cofactor that restricts GATA6 function by inhibiting DNA-binding, resulting in repression of GATA6 transcriptional activation of downstream target genes. Represses GATA6-mediated trans activation of lung- and cardiac tissue-specific promoters. Inhibits DNA-binding by GATA4 and GATA1 to the cTNC promoter (By similarity). Plays a critical role in the development of cardiac hypertrophy via activation of calcineurin/nuclear factor of activated T-cells signaling pathway. Interacts with GATA1 and GATA4 (By similarity). Interacts with beta-dystroglycan. Interacts with GATA6. May shuttle between the cytoplasm and the nucleus. Expressed in the heart (at protein level). Expressed in many tissues with highest abundance in skeletal muscle. The LIM zinc-binding domains and the Cys-rich region mediate interaction with GATA6.