Cytoskeleton Introduction

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Stephen Fish, Ph.D. Marshall University J. C. E.
School of Medicine Fish_at_Marshall.edu
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Note to instructors I use these PowerPoint
slides in cell biology lectures that I give to
first year medical students. Copy the slides, or
just the illustrations into your own teaching
media. We all know that teaching science often
requires compromises and simplification for
specific student populations, or the requirements
of a specific course. Please feel free to offer
suggestions for improvements, corrections, or
additional illustrations. I would be pleased to
hear from anyone who finds my work useful, and am
always willing to make it better. Also, the
images have been compressed to screen resolution
to keep PowerPoint file size down, and I can
provide them at any resolution. Stephen E.
Fish, Ph.D.
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Cytoskeleton
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Intermediate filaments
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Intermediate filament assembly
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Intermediate filament assembly
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Junctions associated with intermediate filaments
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Type V, nuclear lamins

• Make the nuclear fibrous lamina with types A, B,
  C lamins
• Different from other types
• A C form filaments that bind in netlike arrays
• A, B, C depolymerize repolymerize
• B is a single leaflet membrane protein
• B is an anchor for the A C reticulum

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Microtubules
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Microtubule structure
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Microtubule growth if tubulin GTP did not
hydrolyze to GDP after polymerization
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When GTP is hydrolyzed to GDP binding between
dimers changes

• GTP is hydrolyzed to GDP shortly after the a
  dimer is added to a tubule
• As long as there are GTP dimers on the growing
  end the tubule is strong GTP cap

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When growth slows down hydrolysis catches up No
cap disassemble
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Interactions between local soluble GTP-tubulin
concentration the rate of hydrolysis to GDP
results in dynamic instability
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Graph of typical tubule polymerization
depolymerization
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Sherman says
I really like those little heterodimer balls