Co-receptor

Co-receptor

A Co-receptor is a cell surface receptor that binds a signalling molecule in addition to a primary receptor in order to facilitate ligand recognition and initiate biological processes, such as entry of a pathogen into a host cell.

Function

Co-receptors are not directly involved in signal transduction but they assist the primary receptor, often by holding the ligand in place or by facilitating interaction between the ligand and the primary receptor. They can also affect the duration or intensity of the primary receptor's signal.

Types of Co-receptors

There are several types of co-receptors, including:

• CD4 and CD8: These are co-receptors for the T cell receptor. CD4 binds to MHC class II molecules and CD8 binds to MHC class I molecules.
• CCR5 and CXCR4: These are co-receptors for HIV entry into host cells.
• CD28 and CTLA-4: These are co-receptors for the B7 family of costimulatory molecules.

Role in Disease

Co-receptors play a crucial role in the pathogenesis of several diseases. For example, the CCR5 and CXCR4 co-receptors are exploited by HIV to gain entry into host cells. Mutations in these co-receptors can affect susceptibility to HIV infection.

See Also

• Receptor (biochemistry)
• Signal transduction
• Ligand (biochemistry)

References

Co-receptor Resources
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