biology

TAAR2

TAAR2 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 TAAR2 rather than just read about it. In short: Trace amine-associated receptor 2 (TAAR2), formerly known as G protein-coupled receptor 58 (GPR58), is a protein that in humans is encoded by the TAAR2 gene. TAAR2 is co-expressed with Gα proteins; however, as of February 2017, its signal transduction mechanisms have not been determined.

Key takeaways

TAAR2 belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect TAAR2 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of TAAR2 from memory before moving on to harder problems.

Reference excerpt

Trace amine-associated receptor 2 (TAAR2), formerly known as G protein-coupled receptor 58 (GPR58), is a protein that in humans is encoded by the TAAR2 gene. TAAR2 is co-expressed with Gα proteins; however, as of February 2017, its signal transduction mechanisms have not been determined.

Tissue distribution Human TAAR2 (hTAAR2) is expressed in the cerebellum, olfactory sensory neurons in the olfactory epithelium, and leukocytes (i.e., white blood cells), among other tissues. hTAAR1 and hTAAR2 are both required for white blood cell activation by trace amines in granulocytes. Using brain histochemistry staining of mice with LacZ insertion into TAAR2 gene histochemical reaction was found in the glomerular layer of the olfactory bulb, but intensive staining was found in the deeper layer as well. The histochemical reaction was observed in the fibers of the olfactory nerve, in the glomeruli of the glomerular layer, several short axon (SA) cells (outer plexiform layer or granular layer) and neuronal projections that were visualized throughout the depth of the olfactory bulb. Furthermore, LacZ staining was observed in the limbic areas of the brain receiving olfactory input, i.e., piriform cortex molecular area, hippocampus (CA1 field, pyramidal layer), hypothalamic lateral zone (zone incerta) and lateral habenula. In addition, a histochemical reaction was found in the midbrain raphe nuclei and primary somatosensory area of the cortex (layer 5). Real-time quantitative PCR with reverse transcription confirmed TAAR2 gene expression in the mouse brain areas such as the frontal cortex, hypothalamus, and brainstem.

Involvement in the functioning of monoamine systems TAAR2 knockout mice have significantly higher level of dopamine in the striatum tissue than wild-type littermates and lower level of norepinephrine in hippocampus. Also, they have lower levels of MAO-B expression in midbrain and striatum. A significantly higher number of the dopamine neurons was detected in TAAR2-KO mice in the substantia nigra pars compacta. TAAR2 knockout mice have significantly higher level of horizontal activity and lower immobilization time in forced swim test.

Involvement in adult neurogenesis It has been found that TAAR2 knockout mice have an increased number of neuroblast-like and proliferating cells in both subventricular and subgranular zones of the dentate gyrus in comparison to wild type animals. Furthermore, TAAR2 knockout mice have an increased the brain-derived neurotrophic factor (BDNF) level in the striatum. A single nucleotide polymorphism nonsense mutation of the TAAR2 gene is associated with schizophrenia. TAAR2 is a probable pseudogene in 10–15% of Asians as a result of a polymorphism that produces a premature stop codon at amino acid 168.

Involvement in immune cell migration and function TCells, B Cells and Peripheral Mononuclear cells express TAAR2 mRNA. Migration toward TAAR1 ligands required both TAAR1 and TAAR2 expression based on siRNA experiments. In T cells, the same stimuli triggered cytokine secretion while in B cells Immunoglobulin secretion is triggered.

Possible Ligands 3‐Iodothyronamine (T1AM) was identified as a non-selective ligand for TAAR2. Additional TAAR1 ligands, tyramine and phenethylamine trigger TAAR2 dependant actions, though direct binding has not been demonstrated.

See also Trace amine Trace amine-associated receptor

References

This article incorporates text from the United States National Library of Medicine, which is in the public domain.

Illustrations

Worked examples

Example 1 — a first encounter with TAAR2

Start with the simplest possible case. Write down what TAAR2 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 TAAR2 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 TAAR2 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 TAAR2

In research: TAAR2 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 TAAR2 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: TAAR2 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 TAAR2 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 TAAR2 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what TAAR2 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 TAAR2 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is TAAR2 in simple terms?

Why does TAAR2 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 TAAR2?

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 TAAR2.