Concept

CD80

Résumé

The Cluster of differentiation 80 (also CD80 and B7-1) is a B7, type I membrane protein in the immunoglobulin superfamily, with an extracellular immunoglobulin constant-like domain and a variable-like domain required for receptor binding. It is closely related to CD86, another B7 protein (B7-2), and often works in tandem. Both CD80 and CD86 interact with costimulatory receptors CD28, CTLA-4 (CD152) and the p75 neurotrophin receptor . CD80 is a member of the B7 family, which consists of molecules present at APCs and their receptors present on the T-cells. CD80 is present specifically on DC, activated B-cells, and macrophages, but also T-cells CD80 is also a transmembrane glycoprotein and a member of the Ig superfamily. It is composed of 288 amino acids, and its mass is 33 kDa. It consists of two Ig-like extracellular domains (208 AA), a transmembrane helical segment (21 AA), and a short cytoplasmic tail (25 AA). The Ig-like extracellular domains are formed by single V-type and C2-type domains. It is expressed as both monomers or dimers, but predominantly dimers. These two forms exist in dynamic equilibrium. CD80 shares 25% of sequences with CD86; however, CD80 has a ten-fold higher affinity for CD28 and CTLA-4 than CD86. Moreover, CD80 interacts with its ligand with faster binding kinetics and slower dissociation constants than CD86. Both human CD80 and CD86 are located at chromosome 3; the exact region is 3q13.3-q21. Human and murine CD80 share approximately 44% of sequences. Also both human and murine CD80 are able to cross-react with both human and murine CD28. This indicates that the binding site of CD80 is conserved. CD80 can be found on the surface of various immune cells, including B-cells, monocytes, or T-cells, but most typically at antigen-presenting cells (APCs) such as dendritic cells. CD80 has a crucial role in modulating T-cell immune function as a checkpoint protein at the immunological synapse. CD80 is the ligand for the proteins CD28 (for autoregulation and intercellular association) and CTLA-4 (for attenuation of regulation and cellular disassociation) found on the surface of T-cells.

Source officielle

https://en.wikipedia.org/wiki/CD80

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