What Are Ligand Receptors?
Receptor refers to any biological macromolecule that can bind to hormones, neurotransmitters, drugs or intracellular signaling molecules and can cause changes in cell function. [1]
- Chinese name
- Receptor
- Foreign name
- receptor
- Pharmacological concept
- Glycoprotein or lipoprotein
- Existing location
- In the cell membrane, cytoplasm, or nucleus
- Features
- Identify specific signal substances, etc.
- Features
- Specificity of binding, high affinity, etc.
- Receptor refers to any biological macromolecule that can bind to hormones, neurotransmitters, drugs or intracellular signaling molecules and can cause changes in cell function. [1]
Receptor classification
- According to the location of receptors in cells, they are divided into two categories: cell surface receptors and intracellular receptors. The receptor itself contains at least two active sites: one is an active site that recognizes and binds to the ligand; the other is a functionally active site that is responsible for generating a response. This site only binds to the ligand to form a binary complex and deformes it. Only then can a response be generated, thereby initiating a series of biochemical reactions, and ultimately causing the target cell to produce a biological effect.
- Cell membrane receptor
- Most ligand signal molecules are hydrophilic biological macromolecules, such as cytokines, protein peptide hormones, water-soluble hormones, prostaglandins, hydrophilic neurotransmitters, etc., because they cannot penetrate the target cell membrane into the cell, therefore, The receptor for this type of ligand signaling molecule is localized on the target cell membrane.
- Intracellular receptor
- The receptor for most ligand signaling molecules is on the surface of the target cell, because the signaling molecules are hydrophilic and cannot pass through the cell membrane. However, some ligand signal molecules can directly pass through the target cell membrane and interact with cytoplasm or nuclear receptors. By regulating the transcription of specific genes, the expression of gene expression products is up- or down-regulated, thereby starting a series of biochemical reactions. Eventually lead to biological effects in target cells. Such signaling molecules include fat-soluble steroid hormones, thyroid hormones and retinoic acid, and gas nitric oxide.
Receptor function
- The receptor has two functions:
- The first function is to recognize and bind to its own specific signaling molecule (ligand). It is through the recognition of receptors and signal ligand molecules that cells can be filled with countless biomolecules to recognize and receive a specific signal. The second function is to accurately amplify and transmit the recognized and accepted signals to the inside of the cell, thereby initiating a series of intracellular signal cascades, and finally leading to specific cellular biological effects.
Receptor binding to ligand
- As a result of the binding between the receptor and the ligand, the receptor is activated, and the basic steps of subsequent signal transmission of the receptor activation are generated. Under physiological conditions, the binding between the receptor and the ligand is not mediated by covalent bonds, but mainly by ionic bonds, hydrogen bonds, van der Waals forces, and hydrophobic interactions. When binding to a ligand, the receptor has characteristics such as saturation, high affinity, specificity, and reversibility.