The histone H3 lysine 4 methyltransferase, Mll4/Kmt2d, directs overnutrition-induced murine steatosis via its coactivator function for PPARγ2, whereby overnutrition activates Abl1 kinase which phosphorylates PPARγ2, and hence has enhanced interaction with Mll4 (Kim et al., 2016). The gene discussed is PPARG; the disease is steatosis.