PML and acute promyelocytic leukemia: Promyelocytic leukemia-RARα is, like PML, phosphorylated by ERK1/2 in response to As2O3 (Hayakawa and Privalsky, 2004) and, then, highly conjugated to SUMO2/3 (Lallemand-Breitenbach et al., 2008), since it retains two of the three major PML SUMOylation sites at K65 and K160.