Orphan receptor

Orphan receptor refers to a type of protein that has a similar structure to other identified receptors, but whose endogenous ligand has not yet been identified. These receptors are often named after the first compound that is found to activate them.

Overview

Orphan receptors are a subset of the larger family of nuclear receptors. They are called "orphan" because the ligand that binds to them has not been identified, and therefore they are "orphaned" from their binding partner.

Function

The function of orphan receptors is not fully understood due to the lack of knowledge about their ligands. However, they are believed to play a role in a variety of biological processes, including cell differentiation, metabolism, and homeostasis. Some orphan receptors are also implicated in diseases such as cancer, diabetes, and neurodegenerative diseases.

Classification

Orphan receptors can be classified into two main groups: orphan nuclear receptors and orphan G-protein coupled receptors.

Orphan Nuclear Receptors

Orphan nuclear receptors are a subset of nuclear receptors that lack identified ligands. They are involved in a variety of biological processes, including cell differentiation, metabolism, and homeostasis.

Orphan G-Protein Coupled Receptors

Orphan G-protein coupled receptors are a subset of G-protein coupled receptors that lack identified ligands. They are involved in a variety of biological processes, including cell signaling, immune response, and sensory perception.

Research and Clinical Significance

Research into orphan receptors is ongoing, with the hope of identifying their ligands and understanding their function. This could potentially lead to the development of new drugs that target these receptors, providing new treatments for a variety of diseases.

See Also

• Nuclear receptor
• G-protein coupled receptor
• Ligand (biochemistry)