biology

Proliferation marker protein Ki-67

Proliferation marker protein Ki-67 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 Proliferation marker protein Ki-67 rather than just read about it. In short: Proliferation marker protein Ki-67, also known as Antigen Kiel 67 or MKI67, is a protein that in humans is encoded by the MKI67 gene (marker of proliferation Ki-67). Function Antigen KI-67 is a nuclear protein that is associated with cellular proliferation and ribosomal RNA transcription.

Key takeaways

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Reproduce the core statement of Proliferation marker protein Ki-67 from memory before moving on to harder problems.

Reference excerpt

Proliferation marker protein Ki-67, also known as Antigen Kiel 67 or MKI67, is a protein that in humans is encoded by the MKI67 gene (marker of proliferation Ki-67).

Function Antigen KI-67 is a nuclear protein that is associated with cellular proliferation and ribosomal RNA transcription. Inactivation of antigen KI-67 leads to inhibition of ribosomal RNA synthesis, but does not significantly affect cell proliferation in vivo: Ki-67 mutant mice developed normally and cells lacking Ki-67 proliferated efficiently.

Use as a marker of proliferating cells

The Ki-67 protein (also known as MKI67) is a cellular marker for proliferation, and can be used in immunohistochemistry. It is strictly associated with cell proliferation. During interphase, the Ki-67 antigen can be exclusively detected within the cell nucleus, whereas in mitosis most of the protein is relocated to the surface of the chromosomes. Ki-67 protein is present during all active phases of the cell cycle (G1, S, G2, and mitosis), but is absent in resting (quiescent) cells (G0). Cellular content of Ki-67 protein markedly increases during cell progression through S phase of the cell cycle. In breast cancer Ki67 identifies a high proliferative subset of patients with ER-positive breast cancer who derive greater benefit from adjuvant chemotherapy.

Antibody labeling Ki-67 is an excellent marker to determine the growth fraction of a given cell population. The fraction of Ki-67-positive tumor cells (the Ki-67 labeling index) is often correlated with the clinical course of cancer. The best-studied examples in this context are prostate, brain and breast carcinomas, as well as nephroblastoma and neuroendocrine tumors. For these types of tumors, the prognostic value for survival and tumor recurrence have repeatedly been proven in uni- and multivariate analysis.

MIB-1 Ki-67 and MIB-1 monoclonal antibodies are directed against different epitopes of the same proliferation-related antigen. Ki-67 and MIB-1 may be used on fixed sections. MIB-1 is used in clinical applications to determine the Ki-67 labelling index. One of its primary advantages over the original Ki-67 antibody (and the reason why it has essentially supplanted the original antibody for clinical use) is that it can be used on formalin-fixed paraffin-embedded sections, after heat-mediated antigen retrieval (see next section below).

Original Ki-67 antibody The Ki-67 protein was originally defined by the prototype monoclonal antibody Ki-67, which was generated by immunizing mice with nuclei of the Hodgkin lymphoma cell line L428. The name is derived from the city of origin (Kiel, Germany) and the number of the original clone in the 96-well plate.

Interactions Ki-67 (protein) has been shown to interact with CBX3.

See also PCNA - Proliferating Cell Nuclear Antigen, expressed during the DNA synthesis.

Additional images

References

External links Ki-67+Antigen at the U.S. National Library of Medicine Medical Subject Headings (MeSH) http://www.pathologyoutlines.com/topic/stainski67.html Overview of all the structural information available in the PDB for UniProt: P46013 (Proliferation marker protein Ki-67) at the PDBe-KB.

Illustrations

Worked examples

Example 1 — a first encounter with Proliferation marker protein Ki-67

Start with the simplest possible case. Write down what Proliferation marker protein Ki-67 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 Proliferation marker protein Ki-67 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 Proliferation marker protein Ki-67 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 Proliferation marker protein Ki-67

In research: Proliferation marker protein Ki-67 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 Proliferation marker protein Ki-67 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: Proliferation marker protein Ki-67 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cell cycle, Genes on human chromosome 10, Proteins, so understanding it makes those chapters shorter.
In everyday life: Look for Proliferation marker protein Ki-67 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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Frequently asked questions

What is Proliferation marker protein Ki-67 in simple terms?

Proliferation marker protein Ki-67, also known as Antigen Kiel 67 or MKI67, is a protein that in humans is encoded by the MKI67 gene (marker of proliferation Ki-67). Function Antigen KI-67 is a nuclear protein that is associated with cellular proliferation and ribosomal RNA transcription.

Why does Proliferation marker protein Ki-67 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 Proliferation marker protein Ki-67?

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 Proliferation marker protein Ki-67.