biology

Protease-activated receptor 2

Protease-activated receptor 2 is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Protease-activated receptor 2 rather than just read about it. In short: Protease activated receptor 2 (PAR2) also known as coagulation factor II (thrombin) receptor-like 1 (F2RL1) or G-protein coupled receptor 11 (GPR11) is a protein that in humans is encoded by the F2RL1 gene. PAR2 modulates inflammatory responses, obesity, metabolism, cancers and acts as a sensor for proteolytic enzymes generated during infection.

Key takeaways

Protease-activated receptor 2 belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Protease-activated receptor 2 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Protease-activated receptor 2 from memory before moving on to harder problems.

Reference excerpt

Protease activated receptor 2 (PAR2) also known as coagulation factor II (thrombin) receptor-like 1 (F2RL1) or G-protein coupled receptor 11 (GPR11) is a protein that in humans is encoded by the F2RL1 gene. PAR2 modulates inflammatory responses, obesity, metabolism, cancers and acts as a sensor for proteolytic enzymes generated during infection. In humans, we can find PAR2 in the stratum granulosum layer of epidermal keratinocytes. Functional PAR2 is also expressed by several immune cells such as eosinophils, neutrophils, monocytes, macrophages, dendritic cells, mast cells and T cells.

Gene The F2RL1 gene contains two exons and is widely expressed in human tissues. The predicted protein sequence is 83% identical to the mouse receptor sequence.

Mechanism of activation

PAR2 is a member of the large family of 7-transmembrane receptors that couple to guanosine-nucleotide-binding proteins and also belongs to the protease-activated receptor family. PAR2 is activated by several endogenous and exogenous proteases through proteolytic cleavage of its extracellular amino terminus between arginine and serine. The newly exposed N-terminus serves as tethered activation ligand that binds to a conserved region on extracellular loop 2 (ECL2), thereby activating the receptor. These receptors can also be activated non-proteolytically by exogenous peptide sequences that mimic the terminal amino acids of the tethered ligand. Alternatively, cleavage by other proteases at non-signaling sites can render the receptor unresponsive to further protease exposure. Trypsin is the major PAR2 cleaving protease that initiates inflammatory signaling. It was found that even thrombin in high concentrations is able to cleave PAR2. Another PAR2 cleaving protease is tryptase, the main protease of mast cells, which by PAR2 proteolytic cleavage induces calcium signaling and proliferation. PARs have been identified as substrates of kallikreins, which have been related to various inflammatory and tumorigenic processes. In case of PAR2, particularly speaking about kallikrein-4, -5, -6 a -14. PAR2 is known to transactivate TLR4 and epidermal growth factor receptor in diseases.

Function There are many studies dealing with elucidation of PAR2 function in different cells and tissues. In case of human airway and lung parenchyma PAR2 is responsible for increased fibroblasts proliferation and elevation of IL‐6, IL‐8, PGE2 and Ca2+ levels. In mice it participates on vasodilatation. Together with PAR1 its deregulation is also involved in processes of cancer cells migration and differentiation.

Agonists and antagonists Potent and selective small molecule agonists and antagonists for PAR2 have been discovered. Functional selectivity occurs with PAR2, several proteases cleave PAR2 at distinct sites leading to biased signalling. Synthetic small ligands also modulate biased signalling leading to different functional responses. So far, PAR2 has been co-crystallized with two different antagonist ligands, while an agonist-bound state model of PAR2 (with the endogenous ligand SLIGKV) has been determined through mutagenesis and structure-based drug design.

See also Protease-activated receptor Protease-activated receptor 1 Protease-activated receptor 3

References

Illustrations

Worked examples

Example 1 — a first encounter with Protease-activated receptor 2

Start with the simplest possible case. Write down what Protease-activated receptor 2 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Protease-activated receptor 2 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Protease-activated receptor 2 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Protease-activated receptor 2

In research: Protease-activated receptor 2 appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Protease-activated receptor 2 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Protease-activated receptor 2 is common in secondary-school and first-year university syllabi. It links to neighbouring topics G protein-coupled receptors, Genes on human chromosome 5, Receptors, so understanding it makes those chapters shorter.
In everyday life: Look for Protease-activated receptor 2 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Protease-activated receptor 2” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Protease-activated receptor 2 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Protease-activated receptor 2 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Protease-activated receptor 2 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Protease-activated receptor 2 in simple terms?

Why does Protease-activated receptor 2 matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Protease-activated receptor 2?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Protease-activated receptor 2.