Term
| cell motility -- what is it? |
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Definition
Involves:
– Movement of a cell or organism through the environment
– Movement of the environment past or through the cell
– Movement of components in the cell |
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Term
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Definition
• To generate movement, MTs and MFs provide a
scaffold for motor proteins that produce motion at the
molecular level |
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Term
| At what levels can cell motility occur? |
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Definition
• Motility can occur at the tissue level (e.g. muscle
contraction), cellular level (e.g. cell migration), and
subcellular levels (transport of vesicles and organelles)
• Intracellular components can move, e.g., microtubules
of the mitotic spindle separate chromosomes during
cell division |
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Term
| What are the two types of eukaryotic motility systems? |
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Definition
• 1. Interactions between microtubule motor
proteins and microtubules
• 2. Interactions between myosins and actin
microfilaments |
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Term
| Interactions between microtubule motor proteins and microtubules -- when do these happen? give examples |
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Definition
E.g., fast axonal transport in neurons, or the sliding of
MTs in cilia and flagella |
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Term
Interactions between myosins and actin
microfilaments -- when do these happen? give examples |
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Definition
| – E.g., muscle contraction, cell cleavage during cytokinesis |
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Term
| Microtubule-associated motor proteins -- how do they move? |
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Definition
| ‘walk’ along the MTs and provide the force needed for movement |
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Term
| What do microtubules do? How are they structured? |
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Definition
• MTs provide a rigid set of tracks for transport of a
variety of organelles and vesicles
• Traffic toward the minus ends of MTs is considered
“inbound”; toward the plus end is “outbound” |
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Term
| What are the two main kinds of motor proteins that move along microtubules? |
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Definition
| microtubule associated motors: dyneins and kinesins |
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Term
| What is the main kind of motor protein associated with microfilaments? |
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Definition
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Term
| SEE SLIDE 12 -- microfilament and microtubule motor proteins |
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Definition
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Term
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Definition
WHAT DOES IT DO
inhibits fast axonal transport |
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Term
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Definition
WHAT DOES IT DO
inhibits fast axonal transport |
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Term
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Definition
• Proteins and neurotransmitters produced in the cell
body must be transported to the nerve ending
• This process, called fast axonal transport, involves
movement of vesicles and organelles along MTs
• Inhibited by colchicine and nocodazole
• Organelles can be observed moving along filaments
through axoplasm (cytoplasm of axons) at rates of
about 2 nanom/sec |
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Term
| Which two motor proteins are required for fast axonal transport? |
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Definition
• Kinesin I is involved in ATP-dependent transport
toward the plus ends (away from the
centrosome), called anterograde axonal
transport
• Cytoplasmic dynein moves particles (cargo) in
the opposite direction, called retrograde axonal
transport |
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Term
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Definition
-Kinesin I is involved in ATP-dependent transport
toward the plus ends (away from the
centrosome), called anterograde axonal
transport
-needed for fast axonal transport |
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Term
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Definition
-Kinesin I is involved in ATP-dependent transport
toward the plus ends (away from the
centrosome), called anterograde axonal
transport
• Cytoplasmic dynein moves particles (cargo) in
the opposite direction, called retrograde axonal
transport
-needed for fast axonal transport |
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Term
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Definition
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