Involved in lineage commitment of primary hemopoietic progenitors by restricting erythroid formation and enhancing myeloid formation. Interferes with erythropoietin-induced erythroid terminal differentiation by preventing cells from exiting the cell cycle through suppression of CDKN1B/p27Kip1 levels. Suppresses COP1 activity via CSN3 which activates p53 and induces cell cycle arrest. Binds DNA and affects the expression of a number of genes so may function as a transcription factor in the nucleus. Interacts with CENPU (By similarity). Also interacts with NRBP1/MADM, YWHAZ/14-3-3-zeta and HNRPUL2/MANP. NRBP1 recruits a serine kinase which phosphorylates both itself and MLF1. Phosphorylated MLF1 then binds to YWHAZ and is retained in the cytoplasm. Retained in the nucleus by binding to HNRPUL2. Binds to COPS3/CSN3 which is required for suppression of COP1 and activation of p53. Shuttles between the cytoplasm and nucleus. Highly expressed in skeletal muscle, heart, testis. Also found in lung, but not in spleen, thymus, bone marrow, liver and kidney. Expression is activated by FOXJ1. Phosphorylation is required for binding to YWHAZ. Belongs to the MLF family.