Homologous desensitization

Homologous Desensitization is a biological process that occurs in response to prolonged exposure to a stimulus. It is a form of adaptation that reduces the response of cells to a specific agonist, while the response to other agonists remains unaffected. This process is a key mechanism in the regulation of cell signaling and is particularly important in the context of G protein-coupled receptors (GPCRs).

Mechanism

Homologous desensitization begins when a cell is exposed to a high concentration of an agonist for a prolonged period. This leads to the activation of protein kinases, which phosphorylate the GPCR. The phosphorylated receptor is then recognized by beta-arrestins, which bind to the receptor and prevent it from interacting with G proteins, effectively turning off the signal. This process is specific to the activated receptor and does not affect the function of other receptors in the cell, hence the term "homologous".

Role in Disease

Abnormalities in homologous desensitization have been implicated in a number of diseases. For example, in certain types of cancer, GPCRs are overexpressed, leading to excessive cell signaling and uncontrolled cell growth. In these cases, the normal process of homologous desensitization may be disrupted, contributing to the disease process.

Therapeutic Implications

Understanding the process of homologous desensitization could have important implications for the development of new drugs. For example, drugs that enhance the desensitization process could potentially be used to treat diseases caused by overactive GPCRs, such as certain types of cancer.

See Also

• Heterologous desensitization
• G protein-coupled receptor
• Beta-arrestin
• Protein kinase