CEBPA and acute myeloid leukemia: In TRIB1 and TRIB2, the position is occupied invariably by an arginine and an R/L mutation in TRIB1 in this motif (R107L) associated with Down syndrome-related acute megakaryocytic leukemia (AML) enhances ERK (MAPK) protein phosphorylation and C/EBPα (CEBPA) degradation, pointing to its central function in target regulation (Yokoyama et al., 2012).