Back to: MICROBIOLOGY 200 LEVEL
Welcome to class!
Hello there, superstar! I’m truly excited to have you here once again. You’ve been moving like a champion through the world of microbiology, and today, we’re stepping into another interesting topic: Post-Translational Modifications. This one is like the final touch a tailor gives to a freshly sewn agbada — neat, detailed, and essential. Let’s understand it in a way that feels familiar and enjoyable!
Post-Translational Modifications
Let’s imagine a tailor just finished sewing a beautiful native outfit for a big event. But before giving it to the customer, they still need to iron it, sew on the buttons, maybe add embroidery or beadwork, and neatly fold it in a nylon bag. These final touches are not part of the original sewing, but they make the outfit complete, wearable, and presentable.
That’s exactly what post-translational modifications are in biology. After a protein is made by the ribosome, it’s not yet ready to function in the cell. It needs some final touches — modifications — to become active, stable, or to go to the right place in the body.
What Are Post-Translational Modifications?
Post-translational modifications (PTMs) are chemical changes made to a protein after it has been built through translation. These modifications can change the protein’s function, stability, shape, or location.
They usually happen in the endoplasmic reticulum or the Golgi apparatus after the ribosome has made the protein.
Types of Post-Translational Modifications
Phosphorylation
A phosphate group is added to a protein, often to activate or deactivate it.
Like switching a device ON or OFF with a power button.
Very common in cell signalling.
Glycosylation
Sugar molecules are attached to the protein.
This helps with folding, stability, or recognition by other cells.
Very common in secreted and membrane-bound proteins.
Methylation
Addition of a methyl group (–CH₃), often to histones.
Can influence gene expression.
Acetylation
An acetyl group is added, often to the beginning of proteins or histones.
Helps in regulating gene expression and protein function.
Ubiquitination
A small protein called ubiquitin is added to a protein.
Marks it for destruction in the proteasome — like tagging spoiled food for disposal.
Proteolytic Cleavage
Some proteins are produced in inactive forms and later cut to become active.
For example, digestive enzymes like trypsin are activated this way.
Let’s say your mum just cooked a big pot of egusi soup. Before anyone eats it, she may still need to add seasoning cubes, sprinkle crayfish, or garnish with ugu leaves. Those are small additions, but they take the soup from good to great!
That’s how PTMs work — they turn raw, newly made proteins into powerful, functional ones, ready to do their specific jobs in the body.
Summary
- Post-translational modifications are chemical changes made to proteins after translation.
- They help proteins become functional, stable, or properly located in the cell.
- Common types include phosphorylation, glycosylation, methylation, acetylation, ubiquitination, and proteolytic cleavage.
- These modifications occur mostly in the endoplasmic reticulum and Golgi apparatus.
- PTMs are essential for proper protein activity, communication, and overall cell function.
Evaluation
- What are post-translational modifications?
- Mention three examples of PTMs and their functions.
- Where in the cell do PTMs mostly occur?
- Why is phosphorylation important?
- How does ubiquitination affect a protein?
You’ve done wonderfully well today — this topic is a major key in understanding how your body fine-tunes its internal activities. Keep showing up with this energy, because every concept you master brings you closer to your dreams. With Afrilearn, learning is not just smart — it’s joyful, powerful, and tailored just for you. See you in the next exciting class!