biology

Kinesin 13

Kinesin 13 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 Kinesin 13 rather than just read about it. In short: The Kinesin-13 Family are a subfamily of motor proteins known as kinesins. Most kinesins transport materials or cargo around the cell while traversing along microtubule polymer tracks with the help of ATP-hydrolysis-created energy.

Key takeaways

Kinesin 13 belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Kinesin 13 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Kinesin 13 from memory before moving on to harder problems.

Reference excerpt

The Kinesin-13 Family are a subfamily of motor proteins known as kinesins. Most kinesins transport materials or cargo around the cell while traversing along microtubule polymer tracks with the help of ATP-hydrolysis-created energy.

Structure They are easily identified by their three typical structural components including a highly conserved structural domain, catalytic core, and microtubule binding sites. The kinesin-13 family, unlike other kinesins, has an internally positioned motor domain. They were initially named KIF-M because of the unique location of their catalytic core in the middle of the polypeptide between the N-terminal globular domain and the C-terminal stalk but they are truly special due to their versatile nature. The Kinesin-13 family's molecular mechanism is less understood than other classes of kinesins which have their motor domains at one end of the molecule or the other. They are capable of traveling to both the minus and plus ends of microtubules whereas most motors are unidirectional. Thus they can catalytically depolymerize a microtubule from both ends making it a very efficient process. The exact mechanism of Kinesin-13 activated microtubule depolymerization remains unclear, however, recent biochemical and structural studies revealed some more detailed class specific features enabling researchers to formulate a model.) The protein first contacts the side wall of a microtubule. This is not a stable interaction because the convex surface of the catalytic core does not fit to the flat surface of the straight microtubule protofilament. Steric hindrance between the molecule neck and adjacent protofilament further inhibits full contact between protein and the microtubule and only facilitates one-dimensional diffusion along the microtubule. At this time, the protein's nucleotide binding pocket is trapped in an open state so that the structure is not hydrolyzing ATP. Once the motor reaches the end of the microtubule, the protofilament spontaneously curves itself allowing motor to make full contact with the tubulin subunit. More MCAK molecules collectively bind to the curved region supporting the theory that they do not actively peel away the microtubule but they wait patiently for it to adopt this curved conformation. They stabilize the curved conformation by binding to the end of the microtubule and then catalyze depolymerization.

Functions during mitosis The major function of mitosis is to separate replicated sister chromatids, and this is accomplished in part during anaphase A when "kinetochore microtubules (or kMTs)" that link the sister chromatids to opposite spindle poles shorten by depolymerization, exerting forces on the chromatids that pull them to the poles. In Drosophila there is evidence that sister chromatids are moved to opposite spindle poles by a "kinesin-13 dependent pacman-flux mechanism" in which one kinesin-13 isoform, KLP59c, localized to kinetochores facilitates the depolymerization of the end of the kMTs facing the chromatid (pacman), whereas a second kinesin-13 isoform, KLP10A, localized on the spindle poles facilitates the depolymerization of the opposite end of the kMTs facing the poles (flux)

Worked examples

Example 1 — a first encounter with Kinesin 13

Start with the simplest possible case. Write down what Kinesin 13 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 Kinesin 13 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 Kinesin 13 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 Kinesin 13

In research: Kinesin 13 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 Kinesin 13 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: Kinesin 13 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Motor proteins, so understanding it makes those chapters shorter.
In everyday life: Look for Kinesin 13 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 Kinesin 13 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Kinesin 13 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 Kinesin 13 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Kinesin 13 in simple terms?

Why does Kinesin 13 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 Kinesin 13?

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 Kinesin 13.