Ready-to-use ELISA kits are available for the detection of transformed mouse 3T3 cell double minute 4, an alias of the protein, MDM4 regulator of p53. The official gene symbol is MDM4. The protein, with a mass of 54.9 kDa and length of 490 residues, is reported to be nuclear. It is a member of the MDM2/MDM4 family and may be known by other names, including: Mdm4 p53 binding protein homolog, MDM4 p53 regulator, MDM4 protein variant Y, MDM4 protein variant G, and protein Mdm4, and protein Mdmx.