Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

BIO 317 > 16 - Signaling Mechanisms Underlying Axon Guidance II > Flashcards

16 - Signaling Mechanisms Underlying Axon Guidance II Flashcards

1
Q

What is the common effector of the cAMP and PI3K pathway?

A

GSK-3b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the benefit of a feed forward mechanism?

A

It creates a very powerful and forceful signaling mechanism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why is a feed forward mechanism needed for axonal development?

A

It is a prolonged task, which requires relentless signaling to achieve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does the PI3K pathway interact with GSK-3b?

A

Akt can inhibit GSK-3b through phosphorylation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does the cAMP pathway interact with GSK-3b?

A

PKA can inhibit GSK-3b through phosphorylation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

For a western blot of phosphorylated GSK-3b, what is the blot with cAMP and why?

A

Heavy blot, because cAMP activates PKA, which phosphorylates GSK-3b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

For a western blot of phosphorylated GSK-3b, what is the blot with cAMP and PKA inhibitor and why?

A

No blot, because PKA is not active to phosphorylate GSK-3b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

For a western blot of phosphorylated GSK-3b, what is the blot with forskolin and why?

A

Heavy blot, because forskolin activates AC, which leads to cAMP and PKA being active, thus phosphorylating GSK-3b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

For a western blot of phosphorylated GSK-3b, what is the blot with forskolin and PKA inhibitor and why?

A

No blot, because PKA is not active to phosphorylate GSK-3b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

True or false: the PKA pathway and the PI3K pathway only converge at GSK-3b

A

False: these two pathways have many levels of integration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does aPKC interact with GSK-3b?

A

aPKC can phosphorylate GSK-3b and inhibit it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does LKB1 interact with the PI3K pathway?

A

LKB1 can associate with aPKC and lead to cross activation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

True or false: LKB1 can phosphorylate GSK-3b

A

True: this has been seen in some studies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Besides the PI3K pathway, what pathway is Akt an upstream regulator for?

A

The mTOR pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the mTOR pathway do (in terms of axonal development)?

A

Promote translation of PAR-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does Akt interact with the cAMP pathway?

A

Through the mTOR pathway, it can activate translation of PAR-1 (the downstream regulator of LKB1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What three things are needed for a coherent feed forward mechanism?

A
  1. One upstream activator
  2. Diverging branches with the same “message”
  3. Convergence on one downstream target
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

True or false: the cAMP and PI3K pathway can be activated by the same extracellular factor

A

True: they can both be activated by BDNF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

True or false: the cAMP and PI3K pathway can be activated by different extracellular factors

A

True: these pathway can run parallel to one another with different extracellular cues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which extracellular factor can activate both the cAMP and the PI3K pathways?

A

BDNF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What pathways does BDNF promote?

A

Both the cAMP and the PI3K pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does BDNF stand for?

A

Brain derived neurotrophic factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What family of proteins does BDNF belong to?

A

Neurotrophin family of growth factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is BDNF related to?

A

NGF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What does NGF stand for?
Nerve growth factor
26
What functions does BDNF mediate?
Survival, growth differentiation, and synaptic function of neurons
27
What is the receptor for BDNF?
TrkB
28
What is TrkB?
An RTK for BDNF
29
Where are neurotrophins found?
In the brain and in the peripheral nervous system
30
How does BDNF activate the PI3K pathway?
Through the phosphorylation of its RTK TrkB
31
How does BDNF activate the cAMP pathway?
Through the inhibition of PDE4 (increase cAMP levels)
32
What is needed for axons to respond to BDNF in vitro?
LKB1, PKA, and PI3K
33
How can we test that axon formation in response to BDNF depends on LKB1, PKA, and PI3K?
Through genetic and/or pharmacological manipulations
34
If TrkB is phosphorylated, what is the effect on the axon?
It will promote axon development
35
Where does most of the axonal development happen?
At the growth cones
36
What occupies the "palm like" structure of the growth cone?
The actin cytoskeleton
37
Which part of the axon responds to the extracellular environment?
The growth cone
38
What do most of the signaling pathways in axonal development converge on?
Regulation of the cytoskeleton
39
What does MAP stand for?
Microtubule associated protein
40
What are some examples of MAPs?
CRMP-2, Tau, and MAP2
41
What do MAPs do?
Regulate the growth of the microtubule cytoskeleton
42
What type of protein is the Tau protein?
A MAP
43
What is the downstream target of PAR-1?
Tau protein
44
What is the upstream regulator of Tau protein?
PAR-1
45
What does Tau protein do?
Stabilize the assembly of the axon microtubule filaments
46
When is Tau protein activated?
When it is phosphorylated by PAR-1
47
What protein is similar to Tau protein?
CRMP-2
48
What protein is similar to CRMP-2?
Tau protein
49
What happens when Tau protein is phosphorylated?
It can associate with the tubulin monomers and regulate the microtubules
50
True or false: MAPs are only axonal specific
False: there can also be dendritic specific MAPs
51
What is an example of an axonal specific MAP protein?
CRMP-2, Tau protein
52
What is an example of a dendritic specific MAP protein?
MAP2
53
What is MAP2?
A dendrite specific MAP
54
What does MAP2 do?
Mediate microtubule assembly, stabilization, and bundling
55
How do the microtubules interact with the actin cytoskeleton in the growth cone?
They stabilize and penetrate the actin network
56
What needs to happen for axons to experience "bursts of growth"?
Microtubules must penetrate the actin network
57
What is needed to allow the microtubules to invade the actin cytoskeleton in the growth cone?
Actin destabilization (depolymerization)
58
In terms of the cytoskeleton, what is needed to allow for the growth of the growth cones?
Actin instability, and microtubule stability
59
Why is actin instability needed for the growth cones to grow?
Allow for microtubule invasion
60
Why is microtubule stability needed for the growth cones to grow?
Allow for structure to move forward
61
What does colchicine do?
Causes microtubule instability
62
What does taxol do?
Causes microtubule stability
63
What does cytochalasin do?
Causes actin filament instability
64
What does phalloidin do?
Causes actin filament stability
65
Which drug causes microtubule instability?
Colchicine
66
Which drug causes microtubule stability?
Taxol
67
Which drug causes actin filament instability?
Cytochalasin
68
Which drug causes actin filament stability?
Phalloidin
69
Which drugs (that target the cytoskeleton) would promote axon formation?
Taxol and cytochalasin
70
Which drugs (that target the cytoskeleton) would not promote axon formation?
Colchicine and phalloidin
71
If taxol or cytochalasin is presented to the whole cell, what happens?
It will develop multiple axons
72
If taxol or cytochalasin is presented to a specific neurite, what happens?
That neurite will become the axon
73
True or false: taxol could potentially rescue the function of LKB1
True: taxol stabilizes the microtubule cytoskeleton, which is a very downstream regulator
74
What is a good target for the downstream regulation of axonal development?
The cytoskeleton
75
Why is the cytoskeleton a good target for axonal development?
It is one of the most downstream targets that mediates axonal formation
76
What is axonal guidance (or path finding)?
How the axon grows to a specific target
77
True or false: axonal guidance is random
False: it is highly specific
78
True or false: axonal guidance can only create straight lines
False: sharp turns can also be created through axonal guidance
79
What is the purpose of axonal guidance?
Have the axon reach its innervation target (synpase)
80
What happens when an axon reaches its innervation target?
It creates a synapse
81
How does axonal guidance work?
It goes through intermediate proteins until it reaches its innervation target
82
What is needed to choose a route to go from A to B?
A map
83
What information does a map provide?
Where to go (positive cues) and where not to go (negative cues)
84
What "map" is present in axonal guidance?
Molecular cues
85
What do the intermediate proteins do in axonal guidance?
They secrete positive and negative cues to guide the axon
86
In axonal guidance, what do positive cues do?
Signal for the axon to grow towards it
87
In axonal guidance, what do negative cues do?
Signal for the axon to grow away from it
88
How do negative cues cause the axon to grow away from it?
It causes cytoskeleton collapse
89
What cues does the innervation target secrete?
Positive cues
90
What mediates the turns in the growth cone?
The microtubule cytoskeleton
91
What does a positive cue do to the microtubule cytoskeleton?
It causes the filaments to grow in that direction
92
What does a negative cue do to the microtubule cytoskeleton?
It causes the filaments to collapse (depolymerization)
93
What is the net result of a positive and negative cue being presented together in axonal guidance?
A turn is produced
94
What happens to arrays of microtubules in axonal guidance?
Some microtubules can collapse, while others can grow (based on the spatial arrangement of these positive and negative cues)
95
What are the positive cues in axonal guidance?
Chemoattractants
96
What are the negative cues in axonal guidance?
Chemoretractants
97
How does the growth cones detect the chemoattractants and chemoretractants?
Through specific cell surface receptors
98
What is the affect of the chemoattractants and the chemoretractants on the cell (in axonal guidance)?
Activation or inhibition (respectively) of the microtubule cytoskeleton

BIO 317 (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions