Genomics and evolution of the TRIM gene family.

The TRIM family comprises proteins characterized by the presence of thetripartite motifthat is composed of a RING domain, one or two B-box domains and a Coiled-coil region. These proteins are implicated in a plethora of cellular processes such as apoptosis, cell cycle regulation, muscular physiology and innate immune response. Consistently, their alteration results in several pathological conditions emphasizing their medical relevance. The TRIM members domain structure underscores a common biochemical function as E3 ligases within the ubiquitylation cascade, which is then translated into diverse biological processes. The TRIM proteins represent one of the largest families in mammals counting in human almost 70 members. TRIM proteins are metazoan-specific and have been now identified in several species although the great increase in their number was generated in vertebrate species. The important expansion of the number of TRIM genes underlie the success of the tripartite module in ubiquitylation process. Furthermore, their massive diversification among species was achieved through fast evolution of the TRIM genes implicated in pathogen response.