Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PA30251 - Trends & technologies > GPCRs 3 > Flashcards

GPCRs 3 Flashcards

1
Q

What happens when arrestin is phosphorylated by GRK?

A

AP-2 and clathrin are brought to the surface of the membrane.

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

What does clathrin do?

A

It forms a chain of other clathrin molecules down the membrane of the cell.

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

What happens when clathrin has formed a chain of molecules?

A

Invagination of the membrane occurs.

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

What involvement does dynamic have with clathrin?

A

It cleaves the top of the membrane to form a vlathrin coated vesicle.

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

What happens to the GPCR after the involvement of dynamin and clathrin?

A

The GPCR is endocytosed and internalised - it moves into the cell away from the cell surface. A clathrin-coated vesicle is formed.

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

What is the name of the intracellular store of GPCR vesicles?

A

Early endosomes.

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

What are the two fates of early endosomes?

A

Late endosome or lysosome.

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

What happens in the early endosome stage?

A

The agonist comes off the receptor and arrestin drops off

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

What determines the fate of an early endosome?

A

Depends on the receptor type - there are epitotes on the surface of the receptor.

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

What happens if a late endosome is formed?

A

The receptors are recycled back to the cell surface.

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

What happens if a lysosome is formed?

A

The receptor is degraded and the protein goes to the nucleus and is metabolised.

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

What is the first signal for the internalisation of the receptor?

A

Arrestin.

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

What significance does arrestin have in receptor internalisation?

A

As morphine does not have arrestin involved in their mechanisms, these mu-opioid receptors will not be internalised.

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

Which GPCRs are rapidly recycled?

A

Beta2, alpha, mu-opioid, D1.

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

Which receptors are degraded?

A

At1, neurotensin, P2Y, NK1, delta-opioid.

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

Is receptor internalisation beneficial or negative?

A

Beneficial for recycled receptors are resensitization is accelerated, bad for receptors that are lysosomed - prolonged loss of receptor function.

17
Q

What is a receptor that is a target for anti-asthma drugs?

A

The beta-2 agonist.

18
Q

Would beta-2 antagonists be beneficial for asthma?

A

No - reverse effect of agonists - but this is unclear.

19
Q

What happens with consistent treatment of mice with asthma attacks with beta 2 antagonists?

A

They become asthma treatment and make symptoms better - they are inverse agonists not antagonists which explains the effect.

20
Q

What are inverse agonists?

A

Agents that stabilise the inactive state of the receptor and prevent/reduce the probability of constitutive activation. There is a reduced probability of internalisation and receptor degradation.

21
Q

What is the effect of inverse agonists?

A

More receptors are being inserted into the cell membrane (as they are constantly being produced), but degradation is inhibited. There is an overall increase in the number of receptors.

22
Q

What is heterologous desensitization?

A

The activation of one receptor that can affect how the other one acts.

23
Q

What is oligomerization?

A

When two or more receptors are physically linked.

24
Q

What is the difference between a homodimer and heterodimer?

A

Homodimer - two of the same receptors oligomerizing, heterodimer - two different receptors oligomerizing.

25
Q

What is unusual about GABAb receptors?

A

They only signal as heteromers.

26
Q

How does GABAb form heteromers?

A

There are two subtypes that coil and physically attach themselves together. Receptor 1 binds GABA and doesn’t couple to the G protein, whereas receptor 2 can signal through the G protein but GABA cannot bind.

27
Q

What is transactivation?

A

The concept that one receptor is activated by an agonist and the other dimer causes signalling of the G protein.

28
Q

What are the ways in which heteromers can link?

A

N-terminal linking, contact dimer, domain swapped dimer.

29
Q

What are the functional consequences of heterodimerization?

A

Altered signalling, altered pharmacology and altered desensitization/internalization.

30
Q

What can delta-opioid antagonists be used for?

A

They can be linked to mu-opioid agonists to provide beneficial effects.

31
Q

What benefits do delta-opioid antagonists provide when linked with a mu-opioid agonist?

A

They can increase the potency of and decrease the desensitization induced by mu-opioids. They cause less tolerance than the mu-opioid agonist alone.

32
Q

What is a bivalent ligand?

A

One chemical made from two chemical entities linked together - mu opioid and delta opioid receptor.

PA30251 - Trends & technologies (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions