biology

NME4

NME4 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 NME4 rather than just read about it. In short: Non-metastatic cells 4, protein expressed in, also known as NME4, is a protein which in humans is encoded by the NME4 gene. Function The nucleoside diphosphate (NDP) kinases (EC 2.7.4.6) are ubiquitous enzymes that catalyze transfer of gamma-phosphates, via a phosphohistidine intermediate, between nucleoside and dioxynucleoside tri- and diphosphates.

Key takeaways

NME4 belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NME4 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NME4 from memory before moving on to harder problems.

Reference excerpt

Non-metastatic cells 4, protein expressed in, also known as NME4, is a protein which in humans is encoded by the NME4 gene.

Function The nucleoside diphosphate (NDP) kinases (EC 2.7.4.6) are ubiquitous enzymes that catalyze transfer of gamma-phosphates, via a phosphohistidine intermediate, between nucleoside and dioxynucleoside tri- and diphosphates. The enzymes are products of the nm23 gene family, which includes NME4. The first nm23 gene, nm23-H1 (NME1), was isolated based on its reduced expression in a highly metastatic murine melanoma cell line and was proposed to be a metastasis suppressing gene. The human equivalent was obtained by cDNA library screening using the murine gene as a probe and found to be homologous to the Drosophila awd gene. A second human gene, nm23-H2 (NME2), encoding a protein 88% identical to nm23-H1, was subsequently isolated. Both genes were localized on 17q21.3 and their gene products were formerly identified as the A and B subunits of NDP kinases. In mammals, functional NDP kinases are heterohexamers of the A and B monomers, which can combine at variable ratios to form different types of hybrids. These enzymes are highly expressed in tumors as compared with normal tissues. In some cell lines and in certain solid tumors, decreased expression of NME1 is associated with increased metastatic potential; moreover, when transfected into very aggressive cell lines, such as human breast carcinoma, NME1 decreased the metastatic potential. A third human gene, DR-nm23 (NME3), was identified and found to share high sequence similarity with the NME1 and NME2 genes. It is highly expressed in blast crisis transition of chronic myeloid leukemia. When overexpressed by transfection, NME3 suppressed granulocyte differentiation and induced apoptosis of myeloid precursor cells.

References

Illustrations

Worked examples

Example 1 — a first encounter with NME4

Start with the simplest possible case. Write down what NME4 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 NME4 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 NME4 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 NME4

In research: NME4 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 NME4 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: NME4 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Genes on human chromosome 16, Human chromosome 16 gene stubs, so understanding it makes those chapters shorter.
In everyday life: Look for NME4 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 NME4 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NME4 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 NME4 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NME4 in simple terms?

Non-metastatic cells 4, protein expressed in, also known as NME4, is a protein which in humans is encoded by the NME4 gene. Function The nucleoside diphosphate (NDP) kinases (EC 2.7.4.6) are ubiquitous enzymes that catalyze transfer of gamma-phosphates, via a phosphohistidine intermediate, between…

Why does NME4 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 NME4?

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 NME4.