GATA1 and myelodysplastic syndrome: Thus, we focused on MAP3K7 as the cause of GATA-1 dysregulation in our MDS-RS model, because MAP3K7, which is activated by TGF-β, is known to phosphorylate p38MAPK, regulating GATA-1 function both by phosphorylating GATA-1 and by promoting ubiquitination and proteasomal degradation of GATA-1 via MAPKAKP2/HSP2730,31.