Brainscape's Knowledge GenomeTM

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


See full index

SP18: Pharm > Cell Signaling > Flashcards

Cell Signaling Flashcards

1
Q

Roughly 40% of drugs are directed agonists or antagonists for which type of receptor?

A

G protein coupled receptor

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

Activating and inhibiting _____________ is the basis of synaptic transmission of nerve impulses.

A

Ligand activated plasma membrane ion channels

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

T/F: Ligand activated ion channels in the plasma membrane produce a graded potential.

A

True

Have multisubunit proteins

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

In plasma membrane ligand activated ion channels, they typically let in Na+ to ____________ the cell, and let in Cl- to ___________ the cell.

A

Depolarize; hyperpolarize

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

What are some ligands that will depolarize a ligand-activated ion channel in the plasma membrane? Hyperpolarize?

A

Depolarize: acetylcholine, serotonin, glutamate

Hyperpolarize: glycine, GABA

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

Name four ways that drugs can affect plasma membrane ligand activated ion channels.

A
  1. Mimic or block actions of neurotransmitters
  2. Block the channel
  3. Affect NT reuptake
  4. Affect NT metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the most notable ligand activated ion channel found in the organelles?

A

IP3-mediated channel that will release Ca++ from the ER

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

800 functional genes encode ___________.

A

G protein coupled receptors (400 in nose)

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

G protein coupled receptors involve a single polypeptide with ____________.

A

7 transmembrane alpha helices

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

How do agonists activate GPCRs?

A

Bind to the GPCR -> alter the proteins conformation -> leading to the activation of a trimeric G protein

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

What happens inside of the cell after a ligand binds to a GPCR?

A
  1. GTP takes place of GDP in complex
  2. Complex falls into to parts: Galpha and GbetaGgamma
  3. Both parts of the complex participate in cell signaling events
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the steps in the G protein cycle that bring the receptor back to its starting point?

A
  1. The GTP in the Galpha is hydrolyzed to GDP via intrinsic GTPase
  2. After hydrolysis the complex reassembles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which is the major part of the G protein complex?

A

Galpha

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

_______ increases adenylate cyclase activity and ______ decreases adenylate cyclase activity.

A

Galpha(s); Galpha(i)

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

Describe GPCR activation of PKA.

A

Galpha(s) activates adenylate cyclase which converts ATP to cAMP which activates PKA leading to phosphorylation of many proteins

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

How can GPCR activity lead to changes in gene expression in cells?

A

GPCR activation leads to PKA phosphorylation of transcription factors

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

Which liver activity is mediated by PKA?

A

Glycogenolysis (mobilization of glucose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the effect of GPCRs activating phospholipases?

A

Release of signaling molecules embedded within phospholipids of the membrane

19
Q

What are the major actions of Galpha (i and o)?

A

Decrease adenylate cyclase activity and increased phospholipase A2

20
Q

Arachidonic acid is the source of ___________ and ___________.

A

Eicosanoid signaling molecules; prostaglandins

21
Q

Galpha(q) can activate ______________ which will release DAG and IP3 as signaling molecules.

A

Phospholipase Cbeta (PLCbeta)

22
Q

What is the substrate that PLCbeta cleaves into DAG and IP3?

A

PIP2

23
Q

What is the effect of IP3 being released into the cell?

A

Ca++ is released from ER -> Ca++ binds to calmodulin -> altered Ca++/colmodulin complex is able to interact and activate effector proteins

24
Q

What are two examples of proteins activated by Ca++/calmodulin complex?

A
  1. Ca/calmodulin dependent protein kinase

2. Nitric oxide synthase

25
Q

How does DAG activate PKC?

A

PKC needs Ca++ to activate. DAG allows PKC to bind Ca++ tighter so it can work in lower Ca++ concentrations

26
Q

T/F: The agonist-GPCR complex can activate other trimeric G proteins.

A

True

Will eventually turn off by desensitization

27
Q

What are the four major steps in the desensitization and endocytosis of GPCRs?

A
  1. Phosphorylation by a GRK
  2. Binding by beta-arrestin
  3. Formation of clathrin-coated pit
  4. Endocytosis
28
Q

What are the two fates of GPCR that are endocytosed?

A

Recycling or degradation

29
Q

What are some common ligands to receptor tyrosine kinases?

A

Growth factors, differentiation factors, cytokines

30
Q

Binding of ligands to a RYK leads to _________ of the receptor.

A

Dimerization

31
Q

T/F: Some RYKs form homodimers and some form heterodimers but they do not form both.

A

False

Some also form both

32
Q

Describe the process of activation via RYK?

A

Ligand binds -> dimerization of receptor ->transphosphorylation -> docking of signaling molecules -> various signaling cascades

33
Q

Describe the JAK-STAT example of a RYK signaling cascade.

A

JAK kinase phosphorylates receptor after ligand binds -> STAT protein binds to receptor -> phosphorylation of STAT by JAK kinase -> dimerization of STAT protein -> STAT moves to nucleus and activates genes

34
Q

T/F: STAT monomers contain two domains (SH2 and tyrosine) that can be phosphorylated.

A

True

35
Q

STAT proteins mediate biological responses to which ligand?

A

Cytokines

36
Q

Nuclear hormone receptors typically bind what molecule as a ligand?

A

Steroid hormones

(Glucocorticoids, mineralcorticoids, testosterone, estrogens, progesterone)

*also vitamin D, retinoic acid, thyroid hormone

37
Q

Describe the process of activation via a class 1 nuclear receptor.

A

Ligand binding induces complex to fall apart, form a homodimer, and bind to specific DNA element -> binds to coactivators to stimulate transcription

38
Q

T/F: Class I nuclear receptors exist as a complex with heat shock proteins in the absence of a ligand.

A

True

39
Q

What are some examples of ligands for class 1 nuclear receptors?

A

Glucocorticoids, progesterone, estrogens, androgens

40
Q

T/F: Class 2 nuclear receptors bind to target DNA in absence of ligand.

A

True

41
Q

What is a big difference between class 1 and class 2 nuclear receptors?

A

Class 2 binds to corepressors and represses transcription in the absence of a ligand

Class 1 does not bind to DNA targets until bound to a ligand

42
Q

What happens to class 2 nuclear receptors when bound to ligand?

A

Switch from binding corepressors to binding coactivators -> activates transcription

43
Q

What are some examples of ligands for class 2 nuclear receptors?

A

Thyroid hormone, retinoic acid, Vitamin D

SP18: Pharm (8 decks)

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