U2AF2, also known as U2 small nuclear RNA auxiliary factor 2 or U2AF65, is a protein that plays a pivotal role in pre-mRNA splicing. This process is essential for the regulation of gene expression, as it allows a single gene to give rise to multiple protein isoforms through alternative splicing. U2AF2 is part of the U2AF heterodimer, which also includes U2AF1 (U2AF35), and it is responsible for recognizing the 3' splice site during the splicing of pre-mRNA. The protein U2AF2 has a dynamic structure that can switch between open and closed conformations, which affects its ability to bind to the mRNA precursor. This structural flexibility is crucial for the regulation of splicing efficiency at different splice sites. U2AF2 is expressed ubiquitously in the nucleus and is localized to the nucleoplasm and nuclear speckles. It is also detected in the brain, with soma and nucleus in neurons. The protein is involved in several biological processes, including mRNA processing and splicing. U2AF2 is also known to regulate the inclusion of specific exons, such as cardiac troponin-T (TNNT2) premRNA exon inclusion in muscle tissue.