In this video, we're going to begin our lesson on post translational modifications. And so first, we need to recall from our previous lesson videos that translation is the cellular process of building proteins by using the encoded messages of messenger RNA or mRNA. Now, after translation has been complete and the polypeptide chain has been formed, sometimes post translational modifications will take place and post translational modifications are sometimes abbreviated as PTMs. Now, post translational modifications, or PTMs, are covalent alterations that control the protein's activity after translation has been completed. And so there are many different types of post translational modifications and we're going to show you a bunch of post translational modifications down below in our image. But some of the more common types of post translational modifications that you should definitely familiarize yourself with are the four that we have listed down below right here which are methylation, acetylation, ubiquitination, and phosphorylation. So let's take a look down below at our image to get a better understanding of post translational modifications.
And so up here at the top, we're showing you our messenger RNA. And of course, we know that the messenger RNA is going to undergo translation to form our polypeptide chain, our protein whose structure we're showing you right here. Now after translation has been completed this protein, this polypeptide chain can be modified covalently after translation. And that is why it's called post translational modification, because post means after translation. And so you can see a bunch of different post translational modifications that we have listed here. We're showing you nine different post translational modifications. But you don't need to memorize all of these post translational modifications. It will depend upon your instructor or your professor which post translational modifications you should familiarize yourself with. But the ones that we recommend are here across the top. So here we're showing you hydroxylation which is the addition of a hydroxyl group. Number two, what we're showing you is methylation, and methylation is going to be the addition of a methyl group, a CH3 group to the protein, modifying it covalently. Lipidation is going to be the process of adding a lipid to the protein. Acetylation, here is going to be the process of adding an acetyl group, which you can see here, to the protein. Then disulfide bonds are another type of post translational modification that can link, covalently, two separate proteins or can also occur between the same protein disulfide bonds. Ubiquitination is going to be adding a ubiquitin group to the protein which is a small, ubiquitin is a small protein itself that's going to be added to the protein. Sulfonation is gonna be adding a sulfur group which is represented here as, the S to the protein. Glycosylation is going to be adding a carbohydrate to the protein. And then phosphorylation, the last one up here, is going to be adding a phosphate group to the protein after translation.
So once again, there are a bunch of different post translational modifications. There are a lot more than the ones that we've listed here. And so the ones that you are going to need to know depend on your specific professor, but the ones that we recommend that you should definitely be more familiar with are methylation, acetylation, ubiquitination, and phosphorylation. And so this here concludes our brief introduction to post translational modification. And we'll be able to get some practice applying these concepts as we move forward in our course. So I'll see you all in our next video.
