biology

Orexin receptor type 2

Orexin receptor type 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 Orexin receptor type 2 rather than just read about it. In short: Orexin receptor type 2 (Ox2R or OX2), also known as hypocretin receptor type 2 (HcrtR2), is a protein that in humans is encoded by the HCRTR2 gene. It should not be confused for the protein CD200R1 which shares the alias OX2R but is a distinct, unrelated gene located on the human chromosome 3.

Key takeaways

Orexin receptor type 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 Orexin receptor type 2 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Orexin receptor type 2 from memory before moving on to harder problems.

Reference excerpt

Orexin receptor type 2 (Ox2R or OX2), also known as hypocretin receptor type 2 (HcrtR2), is a protein that in humans is encoded by the HCRTR2 gene. It should not be confused for the protein CD200R1 which shares the alias OX2R but is a distinct, unrelated gene located on the human chromosome 3.

Structure The structure of the receptor has been solved to 2.5 Å resolution as a fusion protein bound to suvorexant using lipid-mediated crystallization.

Function OX2 is a G-protein coupled receptor expressed exclusively in the brain. It has 64% identity with OX1. OX2 binds both orexin A and orexin B neuropeptides. OX2 is involved in the central feedback mechanism that regulates feeding behaviour. Mice with enhanced OX2 signaling are resistant to high-fat diet-induced obesity. This receptor is activated by orexin, which is a wake-promoting hypothalamic neuropeptide that acts as a critical regulator of sleep in animals as Zebrafish or Mammals. This protein has mutations in Astyanax mexicanus that reduces the sleep needs of the cavefish.

Ligands

Agonists Danavorexton/TAK-925 – selective OX2 receptor agonist Firazorexton/TAK-994 – selective OX2 receptor agonist Orexins – dual OX1 and OX2 receptor agonists Orexin-A – approximately equipotent at the OX1 and OX2 receptors Orexin-B – approximately 5- to 10-fold selectivity for the OX2 receptor over the OX1 receptor SB-668875 – selective OX2 receptor agonist Suntinorexton – selective OX2 receptor agonist Oveporexton/TAK-861 – selective OX2 receptor agonist Cleminorexton - selective OX2 receptor agonist

Antagonists Almorexant - Dual OX1 and OX2 antagonist Daridorexant (nemorexant) - Dual OX1 and OX2 antagonist EMPA - Selective OX2 antagonist Filorexant - Dual OX1 and OX2 antagonist JNJ-10397049 (600x selective for OX2 over OX1) Lemborexant - Dual OX1 and OX2 antagonist MK-1064 - Selective OX2 antagonist MK-8133 - Selective OX2 antagonist SB-649,868 - Dual OX1 and OX2 antagonist Seltorexant - Selective OX2 antagonist Suvorexant - Dual OX1 and OX2 antagonist TCS-OX2-29 - Selective OX2 antagonist (3,4-dimethoxyphenoxy)alkylamino acetamides Compound 1m - Selective OX2 antagonist

Illustrations

Worked examples

Example 1 — a first encounter with Orexin receptor type 2

Start with the simplest possible case. Write down what Orexin receptor type 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 Orexin receptor type 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 Orexin receptor type 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 Orexin receptor type 2

In research: Orexin receptor type 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 Orexin receptor type 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: Orexin receptor type 2 is common in secondary-school and first-year university syllabi. It links to neighbouring topics G protein-coupled receptors, Genes on human chromosome 6, so understanding it makes those chapters shorter.
In everyday life: Look for Orexin receptor type 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.

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How to study Orexin receptor type 2 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Orexin receptor type 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 Orexin receptor type 2 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Orexin receptor type 2 in simple terms?

Why does Orexin receptor type 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 Orexin receptor type 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 Orexin receptor type 2.