Human Cluster of Differentiation 81 (CD81) Protein

Background

CD81, also known as TAPA-1 (Target of the Anti-Proliferative Antibody 1), is a member of the tetraspanin family, a group of proteins that are widely expressed across various tissues and cell types. Tetraspanins are integral membrane proteins involved in a variety of biological processes, including cell adhesion, migration, proliferation, and signal transduction. CD81 has a well-established role in immune cell function, particularly in the regulation of B and T cell activity, as well as in viral infections. Most notably, CD81 is a critical component in the entry process of hepatitis C virus (HCV) into host cells. The CD81 gene is located on chromosome 11p15.5 and encodes a protein that is involved in the formation of tetraspanin-enriched microdomains. These microdomains facilitate the assembly of various signaling complexes at the cell membrane, influencing the function of associated proteins. CD81 is widely expressed on multiple cell types, including lymphocytes, hepatocytes, epithelial cells, and fibroblasts