Neuroscience Neuron Transport Quiz

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Questions and Answers

What characterizes anterograde transport in neurons?

Transport from the soma to the axon terminal (correct)

Transport from the axon terminal to the soma

Transport using actin filaments

Involvement of retrograde motors

What is the role of kinesin motors in the transport process?

Binding to cargo molecules for retrograde movement

Interacting only with actin filaments

Facilitating anterograde transport of various cargo (correct)

Transporting proteins exclusively in the soma

Which motor protein is responsible for retrograde transport?

Dynein (correct)

Actin

Myosin

Kinesin

How does dynein require assistance to perform its function?

It requires the dynactin complex Signup and view all the answers

In what direction does retrograde transport occur along microtubules?

From the positive end to the negative end Signup and view all the answers

What structural composition primarily defines kinesin motors?

Heterotetramer of light and heavy chains Signup and view all the answers

What type of cargo can kinesin motors transport?

A variety of cargo including vesicles and mRNAs Signup and view all the answers

Which kinesin is specifically noted for moving mitochondria?

KIF1Ba Signup and view all the answers

What is the primary mechanism by which microtubules exhibit dynamic instability?

Hydrolysis of GTP in beta-tubulin Signup and view all the answers

Which class of motor proteins generally moves cargo towards the positive end of microtubules?

Kinesins Signup and view all the answers

Where does catastrophe primarily occur in the microtubule structure?

At the plus (+) end of the microtubule Signup and view all the answers

How does the polarity of microtubules affect their function in axonal transport?

It allows for directional transport of proteins and organelles. Signup and view all the answers

What role do EB proteins play in microtubule dynamics?

They mark growing microtubule ends for observation. Signup and view all the answers

In the context of tissue integrity, why is the orientation of microtubules during cell division important?

It ensures correct positioning of the mitotic spindle. Signup and view all the answers

What is a potential result of incorrect microtubule connections in the mitotic spindle?

Misalignment of chromosomes Signup and view all the answers

Which structure is primarily responsible for nucleating new microtubules?

Gamma-tubulin ring complex Signup and view all the answers

What is the main function of kinesins in neuronal transport?

Facilitate the transport of mRNAs to distal processes Signup and view all the answers

Which protein inhibits the association of KIF5 with synaptic vesicles?

PKA Signup and view all the answers

What is the role of actin microfilaments in neurons?

Provide structural support for dendritic branching Signup and view all the answers

What effect does the binding of ZBP1 to beta-actin mRNA have?

It inhibits translation during transport Signup and view all the answers

How do GTPases regulate transport capacity in neurons?

By modifying cargo attachment to motor proteins Signup and view all the answers

Which process triggers the need for fast local translation in neurons?

Electrical stimuli at the growth cone Signup and view all the answers

Microtubules in neurons are primarily responsible for which function?

Guiding intracellular transport along with motor proteins Signup and view all the answers

What is the significance of phosphorylations in the transport process of kinesins?

They regulate the association with various cargoes Signup and view all the answers

Study Notes

Intracellular Neuron Transport

Two-way transport occurs in neurons, utilizing molecular motors and microtubules as pathways.
Anterograde transport:
- Moves from the soma to the axon terminal.
- Mediated by kinesin motors.
- Transports proteins, vesicles, and organelles.
Retrograde transport:
- Moves from the axon terminal to the soma.
- Mediated by dynein motors.
- Transports organelles, endosomes, and signaling molecules.

Molecular Motors

Kinesin motors are multimeric proteins with:
- Two heavy chains that bind microtubules.
- Two light chains that bind cargo.
Dynein motors are multimeric proteins containing:
- Light, medium, and heavy chains.
- Dynactin, a complex of 11 proteins, is required for function.
- Dynactin binds cargo.
KIF5A, KIF5C, and KIF5B are neuron-specific kinesins.
KIF1Ba and the KIF5 family transport mitochondria.

Microtubule Dynamics

Microtubules (MTs) are dynamic polymers, constantly undergoing growth and catastrophe.
Dynamic instability is driven by GTP hydrolysis in beta-tubulin molecules.
MT dynamism plays a role in:
- Mitotic spindle formation and chromosome alignment.
- Axon growth and guidance.
- Growth cone exploration.

mRNA Transport and Local Translation

mRNA transport to distal neuronal processes is regulated by:
- RNA-binding proteins (RBPs).
- Interaction with kinesins.
- Inhibition of translation during transport.
mRNAs travel as ribonucleoprotein (RNP) complexes in a translationally inhibited state.
Activity can control mRNA transport by affecting the number of RNP granules.

Actin Microfilaments

Actin microfilaments are 8nm thick and composed of actin.
Actin is a conserved and abundant protein, representing up to 10% of total protein in muscle cells.
In neurons, microfilaments:
- Interact with the plasma membrane.
- Contribute to the shape and organization of surface structures.
- Act as pathways for myosin motors, transporting organelles and molecules over short distances.

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Description

Test your knowledge on the intracellular transport mechanisms in neurons, focusing on the roles of kinesin and dynein motors. Understand the differences between anterograde and retrograde transport, and the significance of microtubules in these processes.