Herpesvirus-associated ubiquitin-specific protease (HAUSP, also known as USP7) family, N-terminal MATH (TRAF-like) domain; composed of proteins similar to human HAUSP, an enzyme that specifically catalyzes the deubiquitylation of p53 and MDM2, hence playing an important role in the p53-MDM2 pathway. It contains an N-terminal TRAF-like domain and a C-terminal catalytic protease (C19 family) domain. The tumor suppressor p53 protein is a transcription factor that responds to many cellular stress signals and is regulated primarily through ubiquitylation and subsequent degradation. MDM2 is a RING-finger E3 ubiquitin ligase that promotes p53 ubiquitinylation. p53 and MDM2 bind to the same site in the N-terminal TRAF-like domain of HAUSP in a mutually exclusive manner. HAUSP also interacts with the Epstein-Barr nuclear antigen 1 (EBNA1) protein of the Epstein-Barr virus (EBV), which efficiently immortalizes infected cells predisposing the host to a variety of cancers. EBNA1 plays several important roles in EBV latent infection and cellular transformation. It binds the same pocket as p53 in the HAUSP TRAF-like domain. Through interactions with p53, MDM2 and EBNA1, HAUSP plays a role in cell proliferation, apoptosis and EBV-mediated immortalization.