biology

KDM4A

KDM4A 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 KDM4A rather than just read about it. In short: Lysine-specific demethylase 4A is an enzyme that in humans is encoded by the KDM4A gene. Structure This gene is a member of the Jumonji domain 2 (JMJD2) family and encodes a protein with a JmjN domain, a JmjC domain, a JD2H domain, two TUDOR domains, and two PHD-type zinc fingers.

Key takeaways

KDM4A belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect KDM4A to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of KDM4A from memory before moving on to harder problems.

Reference excerpt

Lysine-specific demethylase 4A is an enzyme that in humans is encoded by the KDM4A gene.

Structure This gene is a member of the Jumonji domain 2 (JMJD2) family and encodes a protein with a JmjN domain, a JmjC domain, a JD2H domain, two TUDOR domains, and two PHD-type zinc fingers. This nuclear protein belongs to the alpha-ketoglutarate-dependent hydroxylase superfamily.

Function It functions as a trimethylation-specific demethylase, converting specific trimethylated histone on histone H3 lysine 9 and 36 residues to the dimethylated form and lysine 9 dimethylated residues to monomethyl, and as a transcriptional repressor.

Clinical significance Alterations in this gene have been found associated with chromosomal instability that leads to cancer. In humans, the role of Kdm4a as an oncogene, or cancer associated gene, is well established. It is implicated in prostate tumors, where it is overexpressed, and stimulates cell proliferation in colon cancer cells, where it promotes formation of the tumor itself. In lung cancer cell lines, where Kdm4a is also overexpressed, it coordinates with other oncogenes (like Ras) to transform normal cells into cancerous cells by inhibiting tumor suppressor pathways such as p53. Suppression of Kdm4a in breast cancer cell lines has shown to reduce cancer cell proliferation through cell cycle arrest, and decrease tumor migration and invasion.

Animal studies In mice models, Kdm4a influences various processes leading up to implantation of the embryo. The expression of this gene is observed in all tissues critical to the female reproductive system, including the hypothalamus, pituitary, ovary, oviducts, and uterus, as well as embryonic development. A knockout of this gene in female mice has shown to negatively interfere with maintaining a maternal uterine environment suitable to receive and implant the blastocyst. It also interferes in the early embryonic development of the female mice's pups prior to implantation, leading to infertility. While mechanisms of normal ovulation and fertilization remain unaffected, infertility may also be partly due to decreased levels of Prolactin, a hormone crucial during the process of pregnancy. A knockout of Kdm4a has no effect on the fertility or viability of male pups.

References

Illustrations

Worked examples

Example 1 — a first encounter with KDM4A

Start with the simplest possible case. Write down what KDM4A 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 KDM4A 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 KDM4A 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 KDM4A

In research: KDM4A 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 KDM4A 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: KDM4A is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 1.14.11, Genes on human chromosome 1, Human 2OG oxygenases, so understanding it makes those chapters shorter.
In everyday life: Look for KDM4A 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 KDM4A in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what KDM4A 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 KDM4A out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is KDM4A in simple terms?

Lysine-specific demethylase 4A is an enzyme that in humans is encoded by the KDM4A gene. Structure This gene is a member of the Jumonji domain 2 (JMJD2) family and encodes a protein with a JmjN domain, a JmjC domain, a JD2H domain, two TUDOR domains, and two PHD-type zinc fingers.

Why does KDM4A 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 KDM4A?

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 KDM4A.