Summary
Cholesterol and sphingolipid-rich membrane microdomains that cluster signalling proteins.
In depth
Rafts are small, dynamic domains enriched in cholesterol and sphingolipids that are more ordered than the surrounding membrane. They concentrate certain proteins, such as GPI-anchored ones and some receptors, helping assemble signalling complexes.
Their existence in living cells is still debated and studied with super-resolution microscopy.
Rafts are tens of nanometres across, short-lived and hard to see directly, so their size and even existence in living cells were debated, and they are now seen as transient nanodomains. Their ordered state arises because cholesterol packs well with saturated sphingolipid tails.
Proposed roles include organising T cell receptor signalling, hosting amyloid precursor protein processing in Alzheimer disease, and entry of viruses such as HIV and toxins such as cholera toxin. Caveolae are specialised raft-related invaginations.
Remember: rafts are better described as regions of locally altered lipid order than as separate rigid islands.
Frequently asked questions
What is Lipid Rafts?
Cholesterol and sphingolipid-rich membrane microdomains that cluster signalling proteins.
Which area of biology covers Lipid Rafts, and how advanced is it?
Lipid Rafts is one of the 51 topics in Biomolecules & Biochemistry. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Protein Folding and Chaperones, Steroids, Phospholipids.
Can you give an example of Lipid Rafts?
Some viruses, including HIV, bud from raft-like regions.
What should I learn before Lipid Rafts?
Work through the Beginner topics in Biomolecules & Biochemistry first, such as Water Properties, Carbon Chemistry, Carbohydrates, then return to Lipid Rafts. Advanced topics assume the Intermediate vocabulary.
What topics are related to Lipid Rafts?
The closest topics to Lipid Rafts are Protein Folding and Chaperones, Steroids, Phospholipids, Free Energy in Biology. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Lipid Rafts?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Lipid Rafts. To practise the whole of Biomolecules & Biochemistry, use the Biomolecules & Biochemistry quiz.
How is Lipid Rafts different from Protein Folding and Chaperones?
Lipid Rafts: Cholesterol and sphingolipid-rich membrane microdomains that cluster signalling proteins. Protein Folding and Chaperones: Chaperone proteins such as Hsp70 help nascent polypeptides reach their native fold and prevent aggregation. Read both side by side and note what each one explains.
How should I study Lipid Rafts step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Protein Folding and Chaperones and explain the difference aloud. Finally, take the Biomolecules & Biochemistry quiz and come back to this page for any question you miss.