biology

KLF4

KLF4 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 KLF4 rather than just read about it. In short: Krüppel-like factor 4 (KLF4; gut-enriched Krüppel-like factor or GKLF) is a member of the KLF family of zinc finger transcription factors, which belongs to the relatively large family of SP1-like transcription factors. KLF4 is involved in the regulation of proliferation, differentiation, apoptosis and somatic cell reprogramming.

Key takeaways

KLF4 belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect KLF4 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of KLF4 from memory before moving on to harder problems.

Reference excerpt

Krüppel-like factor 4 (KLF4; gut-enriched Krüppel-like factor or GKLF) is a member of the KLF family of zinc finger transcription factors, which belongs to the relatively large family of SP1-like transcription factors. KLF4 is involved in the regulation of proliferation, differentiation, apoptosis and somatic cell reprogramming. Evidence also suggests that KLF4 is a tumor suppressor in certain cancers, including colorectal cancer. It has three Cys2His2-zinc fingers at its carboxyl terminus that are closely related to another KLF, KLF2. It has two nuclear localization sequences that signals it to localize to the nucleus. In embryonic stem cells (ESCs), KLF4 has been demonstrated to be a good indicator of stem-like capacity. It is suggested that the same is true in mesenchymal stem cells. In humans, the protein is 513 amino acids, with a predicted molecular weight of approximately 55kDa, and is encoded by the KLF4 gene. The KLF4 gene is conserved in chimpanzee, rhesus monkey, dog, cow, mouse, rat, chicken, zebrafish, and frog. KLF4 was first identified in 1996.

Interactions KLF4 can activate transcription by interacting via its N-terminus with specific transcriptional co-activators, such as p300-CBP coactivator family. Transcriptional repression by KLF4 is carried out by KLF4 competing with an activator for binding to a target DNA sequence (9-12). KLF4 has been shown to interact with CREB-binding protein. Furthermore, KLF4 has also been documented to play a role in long range chromatin interactions across the genome. KLF4 has been shown to play a role in methylation of chromatin thus contributing to higher order architectural changes across the genome. Specifically, KLF4 has been shown to bind to methylated gene motifs causing switching from repressive to active chromatin markers, and causing downstream enhanced transcription of KLF4 gene targets. KLF4 has also been documented to interact with protein arginine methyltransferase 1 (Prmt1), which is involved in post-translational modifications in regards to cell fate decisions via methylation of histones. It has been shown that KLF4 is methylated by Prmt1 and the methylation of KLF4 by Prmt1 prevents the emergence of primitive endoderm progenitor cells, thus showing the role in which KLF4 interactions play with cell development.

Function KLF4 has diverse functions, and has gained attention because some of its functions are apparently contradictory, but mainly since the discovery of its integral role as one of four key factors that are essential for inducing pluripotent stem cells. KLF4 is highly expressed in non-dividing cells and its overexpression induces cell cycle arrest. KLF4 is particularly important in preventing cell division when the DNA is damaged. KLF4 is also important in regulating centrosome number and chromosome number (genetic stability), and in promoting cell survival. However, some studies have revealed that under certain conditions KLF4 may switch its role from pro-cell survival to pro-cell death. KLF4 is expressed in the cells that are non-dividing and are terminally differentiated in the intestinal epithelium, where KLF4 is important in the regulation of intestinal epithelium homeostasis (terminal cell differentiation and proper localization of the different intestinal epithelium cell types). In the intestinal epithelium, KLF4 is an important regulator of Wnt signaling pathway genes of genes regulating differentiation. KLF4 is expressed in a variety of tissues and organs such as: the cornea where it is required for epithelial barrier function and is a regulator of genes required for corneal homeostasis; the skin where it is required for the development of skin permeability barrier function; the bone and teeth tissues where it regulates normal skeletal development; epithelial cell of the mouse male and female reproductive tract where in the males it is important for proper spermatogenesis; vascular endothelial cells where it is critical in preventing vascular leakage in response to inflammatory stimuli; white blood cells where it mediates inflammatory responses cellular differentiation and proliferation; the kidneys where it is involved in the differentiation of embryonic stem cells and induced pluripotent stem (iPS) cells to renal lineage in vitro and its dysregulation has been linked to some renal pathologies.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with KLF4

Start with the simplest possible case. Write down what KLF4 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 KLF4 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 KLF4 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 KLF4

In research: KLF4 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 KLF4 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: KLF4 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Genes on human chromosome 9, Transcription factors, Wikipedia articles with corresponding academic peer reviewed articles, so understanding it makes those chapters shorter.
In everyday life: Look for KLF4 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 KLF4 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what KLF4 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 KLF4 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is KLF4 in simple terms?

Why does KLF4 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 KLF4?

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 KLF4.