Cell Receptor Based On Function

Based on the function of the receptors, scientists have divided them into mainly four categories. They are based on function. They have not divided by the location of the receptors. Based on the function, the four categories are:

1. Ligand-Gated Ion Channels: These are the receptors when they bind with ligands they provide a channel to exchange the ion.
2. G-Protein Coupled Receptors: These are the receptors that are activated when a ligand bind with the G-Protein. After that, it performs certain operations.
3. Catalytic Receptors: These are the receptors that are responsible for the enzyme secretion or the secretion of different substances from the cell.
4. Nuclear Receptors: These are the receptors which are work with the nucleus & help to develop the DNA.

Ligand Gated Ion Channels

These are the cell receptors that are at the cell membrane. These are the channel-like structure. Whenever there is a ligand attached to it. It will open its channel. Using this channel, ions will exchange there. As it is a cell surface receptor. So, its Ligand Binding Domain is on the outside of the cell. There the ligand will attach to it. It helps to move in or out of the Na⁺, K⁺, etc. These types of receptors are often found in Skeleton Muscles.

It has a heteromeric structure. This means, there are many structural subunits present. Each subunit has a Ligand Binding Domain. But there should be only one Effector Domain. That domain is going to be used inside the cell. Also, there is a transmembrane domain. Inside that domain, there are four transmembrane alpha domains. The acetylcholine receptor is one example. Here, the Acetylcholine chemical will bind with the receptor. As a result, the channel will be opened. And the ions will be exchanged there. This is found in the skeleton muscles.

G-Protein Coupled Receptors

These types of cell receptors are also present on the cell membrane. They are a large family of receptors. There is like no ligands are found that can’t able to bind with this type of receptor. This means, there is a wide range of ligands that bind with the G-Protein Coupled Receptors. It is made up of seven transmembrane alpha helices. As they are the receptors are located on the cell membrane, they have their ligand-binding domain at the outside of the cells. Also, this has its effector domain inside of the cell.

G-Proteins are special proteins. They are made up of heterotrimers. Heterotrimers means a special kind of trimer that is derived from different types of monomers. These heterotrimers are also made up of three subunits. They are Alpha, Beta & Gamma Subunits. This type of receptor is being used for creating a large number of hormones. Secretion of several hormones is triggered by the help of these receptors. After binding with any ligand, it starts working inside the cells. Sometimes, it often opens the channels to insert the ions into the cell.

Catalytic Receptors

These are also under the cell-surface receptor category. They are also found on the cell membrane. They are associated with enzymic function. There is a single membrane alpha helix structure inside of Catalytic Receptors Also, as they are located on the cell membrane, there will be the ligand binding domain on the outside of the cell. On the other hand, the effector domain will be inside the cell. They are used for the enzymic secretion from the cell.

Insulin receptors are in this category. It helps to phosphorylate or dephosphorylates proteins. This means sometimes, it helps to add the protein substances to the enzyme & sometimes the present protein substances will be cut down by this receptor. Whenever there is a ligand attached to it, it helps to dephosphorylate proteins. This means it will cut down the protein. Otherwise, it will allow the insertion of the protein into the substances.

Nuclear Receptors

This is only one kind of receptor that does not belong to the Cell-Surface Receptor category. It is from the internal receptor category. This means this receptor is found inside the cell. They are not present outside of the cells. Here, in this case, the Ligand Binding Domain & the Effector Domain both are inside the cell. In this case, the ligand needs to enter the cell to bind with it. After binding with it, it performs some tasks.

Nuclear Receptors are the receptors that can change their position. It first belongs to the Cytoplasm, after attaching it to the ligand, it starts moving toward the nucleus. After that, it enters the nucleus. Then it attaches to the DNA & starts developing the DNA inside of the cell. The Estrogen & Progesterone hormones are from this category.

Communication is an important method to share an emotion or thought with each other. Humans talk to each other for making a communication process. Other animals used some kinds of sound to communicate with each other. Cells in the body also need to communicate. But there is no other method to make a communication. They can’t ever talk or make a sound. But communication is needed also. Without making communication, there will be trouble secreting some chemicals from a certain cell. Those chemical is going to help another cell. So, without communication, the whole process on side of the human body will be stopped. So, they used to communicate with each other with the help of chemicals. Cell Receptor is one component in this case.