In this video, we're going to introduce cell surface receptors. Cell surface receptors, as their name implies, are receptor proteins found embedded in the cell membrane, or in other words, on the surface of the target cell. There are three major types of cell surface receptors that are involved in most signal transduction pathways. Each of these three major types of cell surface receptors operates in its own unique way.
The first major type of cell surface receptor that you all should be aware of is the G protein coupled receptors, or GPCRs for short. You can see GPCR stands for G Protein Coupled Receptors. Taking a look at the image down below, you can see that the GPCR here is in this tannish color, and the G protein portion is highlighted in green. The ligand here can bind to the GPCR, and ultimately, the GPCRs have their own unique way of operating.
The second major type of cell surface receptor that you all should be aware of is the receptor tyrosine kinases, or RTKs for short. The RTKs usually have two domains. You can see the two domains of the RTK. The RTKs, or receptor tyrosine kinases, also have their own unique way of operating and functioning.
The third and final major type of cell surface receptor that you all should be aware of are the ligand-gated ion channels. Down below, we are showing some ligand-gated ion channels, which you can see on the left-hand side are in a closed position. It is not until the ligand binds that the receptor changes conformation into its open position, allowing ions to flow through the membrane. It is the ligand that binds to cause the channel to open up and allow for ions to diffuse across the membrane.
To learn more about the details of each of these different types of receptors and exactly how they operate and function, that's something that you are not typically going to be held accountable for in an introduction to biology course. We do have videos here at Clutch Prep that cover the details of GPCRs, RTKs, and ligand-gated channels. But you'll be able to find those details in our more advanced biochemistry courses. For now, this concludes our brief introduction to the cell surface receptors, and we will be able to talk about the intracellular receptors in our next video. So, I'll see you all there.
