V-set and immunoglobulin domain-containing protein 2, also known as cortical thymocyte-like protein, CT-like protein and VSIG2, is a single-pass type I membrane protein which contains one Ig-like C2-type (immunoglobulin-like) domain and one Ig-like V-type (immunoglobulin-like) domain. VSIG2 is highly expressed in stomach, colon, prostate, trachea and thyroid glands and weakly in bladder and lung. V-set domains are Ig-like domains resembling the antibody variable domain. V-set domains are found in diverse protein families, including immunoglobulin light and heavy chains; in several T-cell receptors such as CD2 (Cluster of Differentiation 2), CD4, CD80, and CD86; in myelin membrane adhesion molecules; in junction adhesion molecules (JAM); in tyrosine-protein kinase receptors; and in the programmed cell death protein 1 (PD1).
