MUM1 (melanoma associated antigen (mutated) 1) is a 710 amino acid protein that becomes phosphorylated by Atm or ATR upon DNA damage and exists as two alternatively spliced isoforms. The gene encoding MUM1 maps to human chromosome 19, which consists of over 63 million bases, houses approximately 1,400 genes and is recognized for having the greatest gene density of the human chromosomes. It is the genetic home for a number of immunoglobulin (Ig) superfamily members, including the killer cell and leukocyte Ig-like receptors, a number of ICAMs, the CEACAM and PSG family and Fc receptors (FcRs).
