In normal cells the tumour suppressor p53 is regulated by and maintained at a low level mainly through Mdm2-mediated ubiquitination and subsequent degradation by the proteasome.
Mdm2 is a RING domain dependent ubiquitin E3 ligase that utilizes its C-terminal RING domain to promote not only p53 ubiquitination, predominantly at the C-terminus of p53, but also to target Mdm2 itself for auto-ubiquitination and subsequent degradation. The isolated Mdm2 C-terminal RING domain (residues 418-491) has been shown to be sufficient for both p53 and self-ubiquitination activity.
Recombinant catalytic RING domain expressed with N-terminal GST-tag.
