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Lecture 6

CBIO 3400 Lecture Notes - Lecture 6: Vaccinia, Endoplasmic Reticulum, Atp Hydrolysis

Cellular Biology
Course Code
CBIO 3400

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CBIO 3400
Lecture 6: Dynein Continued and Mitosis and Cytokinesis
Overview of Dynein Motor: Dynein motor binds to ATP and changes conformation of stalk,
brining domain 1 and 2 together. ATP hydrolysis induces a kink in the linker arm. The
straightening of the linker arm is the power stroke which occurs with the release of Pi.
Repeating this cycle moves the motor forward on a microtubule.
Microtubule binding domain and ATPase site are separated.
4 AA domain binds ATP
hydrolysis of AAA1 is critical for activity
Microtubules & their motors generate the intracellular membrane network
Kinesins motors
o Examples of the endoplasmic reticulum (ER) network: Kinesins motors drag ER
into tubule formation
o Kinesin motors are always trying to rebuild the ER network throughout the cell
by extending the ER membrane
o Viruses hijack kinesins to move them to plasma membrane: example vaccinia
Dyneins motors
o Example of the Golgi apparatus and dyneins; dyneins are constantly grabbing
pieces of the Golgi and bringing it back to reform Golgi apparatus
o When you add colchicine to the cell, the microtubules start to disappear
o W/o microtubules, your Golgi will disassemble and fall apart
Motors are forced into a constant struggle with each other
Cells can use both dyneins and kinesins to work in your body.
Tug of war between kinesin and dynein: additional layers of regulation
o Motor competition/cooperation provides an additional level of regulation and
cAMP, a second messenger, increase resulting in the inactivation of
kinesin allowing dynein to win the tug of war*
Turn of kinesin and dynein can run at full speed
Example: Fish Melanocytes
o Driven by extension of chromtatophores and retraction which are both motor
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