Biophysics 6702
Tony Brown
Flipped classroom: Cytoskeletal motor proteins
1. View these online before class:
http://www.ibiology.org/ibioseminars/cell-biology/ron-vale-part-1.html
http://www.ibiology.org/ibioeducation/making-discoveries/discovery-talk-looking-for-myosin-and-findingkinesin.html
2. Come to class prepared to address the following questions, as well as to ask your own questions:

How many different cellular events or processes can you think of that involve cytoskeletal motors?

What were the key observations that led to the discovery of kinesin?

What special property of kinesin was exploited to purify this motor? This may require a little research
if you are up for it!

What are the similarities and differences in myosin, kinesin and dynein structure and function?

How many distinct families of myosin, kinesin and dynein motors are there in mammals such as
humans or mice?

What determines the direction of movement of a cytoskeletal motor?
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What determines the velocity of a cytoskeletal motor?
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What is the step size of kinesin or dynein motors and why?
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What is meant by the processivity of a cytoskeletal motor?
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Why is muscle myosin non-processive while conventional kinesin has evolved to be processive?
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What is the force generated by a single motor?

How does the efficiency of cytoskeletal motors compare to automobiles?

What is the gravitational attractive force produced by you and your friend at arms length and how
does it compare to the force produced by one molecular motor (let us say that it is 5 pN)?

What do cytoskeletal motors use as their energy source and how is this energy converted into work?

In addition to the myosins, dyneins and kinesins in cells there are also other proteins that we could
consider to be motors. Brainstorm and come to class with your ideas!

What diseases involve mutations in cytoskeletal motors? This may require a little research.

How do muscle myosin and kinesin differ in their motility cycles?

What are the functions of the head and tail domains of molecular motors?

Which domains of molecular motors are most highly conserved within a motor superfamily (e.g.
between all kinesins or between all myosins) and why?

Why is it important for the cell to organize its microtubules with uniform polarity (e.g. microtubule plus
ends extending away from the centrosome)?

In the in vitro gliding assay, kinesin is bound nonspecifically to the glass, facing in all directions. Why
is it that the microtubules are moving continuously in one direction and are not in a tug-of-war? What
end of the microtubule is “leading” (plus or minus end) as they travel across the glass?

Why does a cell have so many different types of molecular motors?