CD2BP2 (CD2 (cytoplasmic tail) binding protein 2), also known as LIN1, Snu40, FWP010 or U5-52K, is a 341 amino acid protein that localizes to both the nucleus and the cytoplasm and contains one GYF domain. Expressed in a variety of tissues, CD2BP2 exists as a bifunctional protein that, in the nucleus, is a component of the U5 small nuclear ribonucleoprotein complex and, in the cytoplasm, binds to the tail of the CD2 antigen. Via its multifunctional activity, CD2BP2 participates in RNA splicing and regulates CD2-triggered T-lymphocyte activation. The gene encoding CD2BP2 maps to human chromosome 16, which encodes over 900 genes and comprises nearly 3% of the human genome.