 Myc cleavage is mediated by the calpain family of calcium-dependent cytosolic proteases.The cleavage of Myc by calpains is a constitutive process but is enhanced under conditions that require rapid downregulation of Myc levels, such as during terminal differentiation.Upon cleavage, the C-terminus of Myc (containing the DNA binding domain) is degraded, while Myc-nick, the N-terminal segment 298-residue segment remains in the cytoplasm.