biology

PCAF

PCAF 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 PCAF rather than just read about it. In short: P300/CBP-associated factor (PCAF), also known as K(lysine) acetyltransferase 2B (KAT2B), is a human gene and transcriptional coactivator associated with p53. Structure Several domains of PCAF can act independently or in unison to enable its functions.

Key takeaways

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

Reference excerpt

P300/CBP-associated factor (PCAF), also known as K(lysine) acetyltransferase 2B (KAT2B), is a human gene and transcriptional coactivator associated with p53.

Structure Several domains of PCAF can act independently or in unison to enable its functions. PCAF has separate acetyltransferase and E3 ubiquitin ligase domains as well as a bromodomain for interaction with other proteins. PCAF also possesses sites for its own acetylation and ubiquitination.

Function CBP and p300 are large nuclear proteins that bind to many sequence-specific factors involved in cell growth and/or differentiation, including c-jun and the adenoviral oncoprotein E1A. The protein encoded by the PCAF gene associates with p300/CBP. It has in vitro and in vivo binding activity with CBP and p300, and competes with E1A for binding sites in p300/CBP. It has histone acetyl transferase activity with core histones and nucleosome core particles, indicating that this protein plays a direct role in transcriptional regulation.

Regulation The acetyltransferase activity and cellular location of PCAF are regulated through acetylation of PCAF itself. PCAF may be autoacetylated (acetylated by itself) or by p300. Acetylation leads to migration to the nucleus and enhances its acetyltransferase activity. PCAF interacts with and is deacetylated by HDAC3, leading to a reduction in PCAF acetyltransferase activity and cytoplasmic localisation.

Protein interactions PCAF forms complexes with numerous proteins that guide its activity. For example PCAF is recruited by ATF to acetylate histones and promote transcription of ATF4 target genes.

Targets There are various protein targets of PCAF's acetyltransferase activity including transcription factors such as Fli1, p53 and numerous histone residues. Hdm2, itself a ubiquitin ligase that targets p53, has also been demonstrated to be a target of the ubiquitin-ligase activity of PCAF.

Interactions PCAF has been shown to interact with:

See also Transcription coregulator Acetyltransferase

References

External links PCAF protein, human at the U.S. National Library of Medicine Medical Subject Headings (MeSH) NURSA C105

Illustrations

Worked examples

Example 1 — a first encounter with PCAF

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

In research: PCAF 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 PCAF 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: PCAF is common in secondary-school and first-year university syllabi. It links to neighbouring topics Gene expression, Genes on human chromosome 3, Transcription coregulators, so understanding it makes those chapters shorter.
In everyday life: Look for PCAF 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 PCAF in 20 minutes

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

Frequently asked questions

What is PCAF in simple terms?

P300/CBP-associated factor (PCAF), also known as K(lysine) acetyltransferase 2B (KAT2B), is a human gene and transcriptional coactivator associated with p53. Structure Several domains of PCAF can act independently or in unison to enable its functions.

Why does PCAF 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 PCAF?

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 PCAF.