|
University of Texas Medical Branch |
Cell Biology Graduate Program |
Microtubules are conveyer belts inside the cells. They move vesicles, granules, organelles
like mitochondria, and chromosomes via special attachment proteins. They also serve a
cytoskeletal role. Structurally, they are linear polymers of tubulin which is a globular
protein. These linear polymers are called protofilaments. The figure to the left shows a
three dimensional view of a microtubule. The tubulin molecules are
the bead like structures. A protofilament is a linear row of
tubulin beads. Microtubules may work alone, or join with other proteins to form more complex structures called cilia, flagella or centrioles . In this unit we will cover all of these structures. The reading assignment is Alberts et al Molecular Biology of the Cell, Garland Publishing, N.Y., pp 803-820. Note: many of the photos are from the text, or from Histology texts by Bloom and Fawcett used by our students. They are for illustration at this site only and for individual student use. For updated information please consult:
http://www.cytochemistry.net/Cell-biology/microtub.htm
View Menu of Cell Biology Topics. |
 What is the structural
subunit of a microtubule? What ingredients would you need to make a microtubule in a test tube? Why is the temperature
important during assembly of a microtubule? What is the difference between nucleation and elongation? What would happen if you substituted a nonhydrolyzable analog of GTP for the
GTP? What clue does this give you about the role of GTP? With respect to microtubules, what is dynamic instability and why is it
important to the cell? What is the GTP cap and
how could the cell use it to regulate microtubule growth? How do Microtubule
associated proteins help with the functional differentiation of a cell? Think about
your past studies of neurons, for example. How might microtubules organize different
functional domains? What about polarized cells, like the intestinal epithelial cell? What is the significance of acetylation or detyrosination of alpha tubulin
in a microtubule? What are kinesins
and dyneins and how do they work? What in vitro
experiments are used to detect direction of movement along the microtubules? Which drugs would
you use to stabilize microtubules? Which would you use to prevent mitoses? Why are some of
these drugs useful in the treatment of cancer? What are cilia and flagella and what is
the basic difference in structure between the two? How are cilia and flagella structured to
be mobile? What is an "axoneme"? What is the role of dynein in the
movement of cilia and flagella? What is the role of nexin and the
radial spokes in the movement of cilia and flagella? What will happen if you were to
digest the nexin and radial spokes with proteases? Why are centrioles important
to cilia function? What are basal bodies? How is the internal
structure of centrioles and cilia or flagella different? How do centrioles control the direction
of the ciliary beat? How do centrioles replicate? |
| Microtubule Structure | Formation of microtubules. | Microtubule Associated Proteins |
| Drug effects on microtubules | Cilia and Flagella | Centriole origin and function |
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Last updated: 12/05/03
© copyright 1998 Gwen V. Childs, Ph.D.
URL Address: http://cellbio.utmb.edu/microanatomy/
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