Cell Biology | Translation: Protein Synthesis

They will degrade too, because why does this happen? Because at this point you press a stop codon and once you press that stop code, the

translation

process ends, the translocon closes and the peptide is released without signal. sequence in it towards the lumen of the rough er and then the ribosomes and the mRNA will dissociate and that has covered the ribosomal translocation process now very quickly when you have this ribosomal translocation process coming and binding with the rough er. I want you to know why we already talked about it. The three reasons why this would occur are

protein

s that are going to be secreted

protein

s and that is why they need to go to the roughest area, then to the Golgi, form a vesicle and then be excreted or incorporated into the membrane.

The second thing is they are going to be a membrane protein and the last reason is that they are going to become lysosomal proteins. Well, these are the three reasons why they would be harder ribosomes. Well, I need you to know that and it's a really simple process because whenever If you know, go back to this diagram here, if I take a protein, it's synthesized raw, so where does it have to go to the Golgi? Then from the Golgi it has to be packaged into vesicles and those vesicles can go. to the

cell

membrane they get incorporated, they go to the

cell

membrane, they get excreted or they can become a lysosome, okay, that's the purpose of why we go through that process with the tough ones.

What about the others? I know you guys are probably like that, Zack. What happens to all those free ribosomes that don't bind to the rough ribosomes? That? As? Where are you going? What do they do? If we talk about, let's say we use a line here and say that these structures are where proteins are found. that will be incorporated into these, will come from free ribosomes and which we already talked about, these proteins that will be incorporated into cell membranes, will be secreted or converted into lysosomes, will be rougher ribosomes, we already know those of Rougher and more secreted proteins Proteins membrane Lysosomal proteins What happens to free ribosomes?

Where are those proteins going? If it is only in the free ribosomes. These proteins will be for cytosolic proteins. What are the reasons why we have cytosolic proteins? Just use a very simple example: many of the metabolic processes that occur in the cell glycolysis that occurs in the cytoplasm some other steps that occur in the cytoplasm we need those proteins to catalyze things that are in the cytosol the second proteins that are incorporated into the nucleus different types of enzymes that are involved in things that are involved in the transcription of DNA things that are involved in the replication and modification of things, so we also need them for nuclear proteins proteins that are actually going to be involved in the processes mitochondrial certain metabolic processes that are involved there, so mitochondrial enzymes and the last one is the enzymes that are very, very important, catalases and a lot of other enzymes that are involved within the peroxisomes, so the peroxisomal enzymes are okay, very, very important to remember those things, okay, the free ribosomes give way to the cytosol, the nuclear mitochondrial peroxisomal proteins and the rough vr. gives way to membrane-bound proteins, lysosomes, and excreted proteins.

As simple as that: now we have created the protein, or we have it, we have produced the protein through free ribosomes or we have created the proteins from the rough endoplasmic reticulum. Now what do we have to do? We have to modify the protein in a couple of different ways, let's talk about that very briefly, okay guys, right now we went from DNA, transcribed it, made mRNA, then translated and made proteins. In this case, we made a protein, we went through all these stages in video transcription sequence and then

translation

in this video. Now what we're going to do is take this protein that we've synthesized, whether it was through the free ribosomes or whether it was through the rough endoplasmic reticulum ribosomes and we have to modify them a little bit, in other words, we add or cut things, that's all, we add, we cut, let's give some examples, we are not going to go too much ham, let's say that in one of these I add a residue of sugar.

I'm just going to represent that with a g, what is this called when you add a sugar residue to a protein as a wobble, so it could be a reaction called glycosylation and we'll do that. We'll talk briefly about a couple of examples of these a little later, but that's one thing: I add a sugar residue to these proteins. The next thing you could do is add a lipid to these proteins. What do you think is called lipidation? We'll just represent this little thing called lipidation and talk about the reasons why this is important. The next thing we could do is add phosphate groups so we can add phosphate groups and so just show the phosphate groups here, what is this called phosphorylation?

We could add hydroxyl groups, what is this called hydroxylation? Well, what else could I do? You could add like a methyl group here, let's put in a couple of methyl groups. You could add an acetyl group or I. You could cut some of the amino acids, so let's cut or trim some of the amino acids. What would this be called if I added a methyl group? This is called methylation. What would it be called if I added an acetyl group? It's not difficult, right, an acetyl group you would call acetylation and the last thing is I could cut it, so here it would just represent maybe I'm going to remove some of these amino acids from the reaction if I cut some of these amino acids.

Well, what is that called? Actually, we specifically call it trimming. These are the basic kind of most important modifications that you really need to know when you're taking a protein and doing things to it, but glycosylation, lipidation, phosphorylation, hydroxylation. methylation, acetylation and trimming, what are examples of those that are something important that you should really know, I'm not going to exaggerate, but just think of examples, if I took a protein and added a sugar residue to it, what would be a reason? that I would like to do that, the best example that I can think of is the antigens, okay, so you know, like your red blood cells, your red blood cells, you have different antigens, like the a antigens, the b antigens, the rh antigens, those have sugar residue. proteins with sugar residues and they help identify what type of protein you have, which can determine your blood type correctly, so that's an example, so it can be good for identifying particular proteins or specific antigens of a cell, too it's good for transporters, you know, transporters, different types of channels, like the glutamate channels that we talked about in this membrane transport or other different types of voltage-gated ion channels, which can sometimes have some sugar residues. lipidation, are good for the proteins that are going to be incorporated. in the cell membrane, so these will be lipid proteins that are good for the cell membrane and the membranes of the organelles, for example, the rough endoplasmic reticulum, which is a phospholipid bilayer in which we could use some proteins with residues of sugar lipids, the golgi, the smooth. endoplasmic reticulum things like that or the phosphorylation of the cell membrane itself, this is really important.

I really need you to remember this. Use the example we've talked about a million times, like protein kinase A or cyclin-dependent kinases, things like that. We've talked a lot in other videos, these guys add phosphate groups correctly, so if you had a protein here and we added a phosphate group that could activate the protein or it could inhibit it and that's important in many cells as you know your cell cycle when you go from your g1 phase to your s phase to your g2 phase through mitosis, we phosphorylate particular proteins that modulate that activity or modulate cell signaling pathways, so this is very, very important, hydroxylation is very, very key to doing collagen

synthesis

.

Collagen is extremely important because it is incorporated into our bones, our cartilage, our connective tissue, our basement membranes and hydroxylation is one of the most important ways we produce collagen. Okay, methylation, acetylation, it's better to talk about this and I know you ninja nerds know this, we literally have. I just talked about it in the structure and organization of DNA. If I methylate a histone protein, what do you do if you add a methyl group to it? Does transcription decrease or increase? It keeps the interaction tight, so you can fit an RNA polymerase between that. No.

That would decrease transcription if I put an acetyl group on it, it relaxes the DNA, increases the space that the RNA polymerase can enter, reads it and does what increases transcription, so something as simple as modifying our protein that way can make a big difference and my favorite example is cutting back I like to think about this, let's say you just worked out, you made some gains, you're going to go home and eat chicken breasts, you know it tastes like a bicycle tire, you know, because sometimes you know. chicken isn't as good, but you're still trying to get your gains, you're getting your protein and when you do that, the protein goes into your small intestine and you have a particular enzyme called trypsinogen, you know, an enzyme called trypsinogen, trypsinogen. something like the precursor, it's not active, but if I take and use an enzyme that cuts trypsinogen and converts it to trypsin, I'm going to cut a piece off, this is the inactive protease, this is the active protease, if I activate it By cutting it some pieces, now you can go and do shiatsu with the proteins that I ate from the chicken so that I can absorb them, those are simple examples of how we can modify proteins that can be activated or deactivated and incorporated into a The membrane must be particularly an antigen, all these different things , so you take proteins and you modify them for particular cellular examples and that concludes our video on protein

synthesis

translation.

Alright ninjas, in this video today we talk about protein translation or protein synthesis. I hope that made sense. And I hope you enjoyed it, engineers as always, until next time.