Broken Tacos and Why Proteins Aren’t As Fortunate As Us
Alt title: The Heat Shock Response And Its Role in Proteostasis. But that sounds just a little less cool. Or not. Depending on who you are.
Have you ever broken a taco shell or had some component of your meal crumble, only for your parents to tell you that it’s okay because it’ll all get broken up in your stomach anyways?
Or maybe you’ve stained or ripped your favorite shirt, and told yourself that it isn’t noticeable and you can still wear it.
First off, SAME. To all of these questions/scenarios. And it seems that most of the time when you change the look of something or something becomes less visually appealing, the function remains the same. You can still use that slightly-nicked waterbottle. It just might not look as nice.
This holds true for a lot. Your clothes, your appliances, your food. But there is one fateful thing for which this is so untrue. Proteins (things in your cells that perform uber-specific functions, like an antibody!).
Okay, odd transition, I know. But this is true! The function of proteins is determined by their folds and specific shape. If any proteins were to become misshapen, they would lose their function.
When proteins do become misshapen, this is called denaturing. When proteins get denatured, since they perform most of their jobs by binding to other molecules at specific sites or using their specific structure to move themselves from place A to place B, they stop functioning properly.
An example of a protein that heavily relies on its shape to perform its function is an antibody. You might have heard about this guy in biology class or when talking about COVID-19. Antibodies are your central line of defense against foreign viruses, and other substances. They have a Y-like shape, and they use it strategically: they bind to foreign molecules on one end while recruiting other immune-system proteins with the other.
If they lost that Y-shape, they’d lose a lot of ability to do their job.
So, Nina, this is interesting and all, but what’s the real world application? What about all those fancy words you mentioned in the title? I’m kind of tired of hearing about tacos and antibodies. Tell me more about other stuff!!
Fine fine fine! So, basically, proteins do get denatured sometimes. Sometimes this is because of temperature changes or pH changes. Or certain compounds and ions that interact with the protein.
And when this happens, your body doesn’t want to have proteins that don’t do their job, or worse, do it incorrectly! So this is where proteostasis comes into play. Yes, that does sound like homeostasis for a reason. It’s the process that makes sure the health of the proteins in the cell and the overall human (you!) is maintained. Aka keeping balance and health in your overall system.
Your body has several ways to keep your system in a state of good proteostasis, and I’ll talk about one of them today. It’s called chaperone-mediated autophagy!
Basically, when proteins are misfolded, there is a certain subset of ‘chaperone’ proteins that go around in your cells and find all the misfolded proteins. Once they find them, they take them to your lysosomes and have them degraded. Heat shock proteins are the main ones that do this, but there are a few other helpers.
This helps your body maintain proteostasis, as it can easily dispose of the proteins that would otherwise weigh it down and potentially cause harm in the long run (by doing functions incorrectly or not doing them at all!).
One issue is that these proteins decrease in amount as you age -> due to changes in how much they are made because epigenetics! If you want more of an explainer on epigenetics and aging, check out my next article, which’ll come out soon.
But a quick overview of epigenetics (because I’d hate to keep you waiting :)) is that your body has this thing called an epigenome, and it’s what controls the amount that each of your genes are expressed. Your genes are what make your proteins, and the more one is expressed, the more of that protein that will be made. Your epigenome changes with age, and thus the amount that genes are expressed changes as well.
Since these heat shock proteins decrease in amount with age, our body is less able to deal with misfolded proteins, which can contribute to diseases like Alzheimer’s, vascular dementia, and Parkinson’s (I’m hoping to work on this :)).
Other parts of chaperone-mediated autophagy break down as well with age, which can lead to an overall inefficient system, unfortunately (I might write another article on chaperone-mediated autophagy’s ways of breaking down!).
Anyways, I hope this article didn’t make you crave broken tacos too much. And if it did, go grab some tacos and be grateful that your heat shock proteins are up and running!
TL;DR:
- Proteins rely on their shape and folding patterns for proper function
- They can unfortunately get ‘denatured’ — aka they can have issues with folding or shape sometimes.
- Your body maintains protein health/overall ‘protein homeostasis’/proteostasis through a system called chaperone-mediated autophagy.
- Your body is less able to do this important function with age, which contributes to many aging-related diseases!
Yes, I am back! I’ve decided to start writing again. Yay! Anyways, obligatory plug of my newsletter here: ninakhera.substack.com. :) I’m a teen who loves learning and aims to eradicate dementia someday! Find out more about me here: ninakhera.com.
