This family of proteins is present in the nucleus [1]. The function of MDM1 is not known.

1: A gene amplified in a transformed mouse cell line undergoes complex transcriptional processing and encodes a nuclear protein. Snyder LC, Trusko SP, Freeman N, Eshleman JR, Fakharzadeh SS, George DL; J Biol Chem. 1988;263:17150-17158. PMID:3182840