GATA4 is a 46 kDa member of the GATA family of zinc finger containing transcription factors that is involved in the development of cardiac hypertrophy and remodeling, and plays a critical role in regulating basal and agonist or stress induced gene expression in cardiac and smooth muscle cell types. GATA4 contains a conserved MAPK phosphorylation site at serine 105 within the transcriptional activation domain. Serine 105 of GATA4 is phosphorylated in response to agonist stimulation through MEK 1 ERK1 / 2, and weakly through JNK or p38 MAPKs.