Cell signalling Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

____signalling may affect cells at a great distance, and the concentration of signal molecules is generally high

A

endocrine

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

____signalling involves local mediators at low concentrations and a localized effect

A

paracrine

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

____signalling involves a cell stimulating its own signalling pathway

A

autocrine

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

___signalling involves direct contact between the two cells involved in signalling

A

Juxtracrine
contact-dependent contact between a cell surface signalling molecule and a receptor of another cell

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

___signalling occurs when signal molecule moves directly between cytosols of two cells via bridge such as a gap junction or plays odesa at

A

direct

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

If the signal molecule is permeable to the membrane the receptor will be_____. Where does this happen?

A

cytosolic.This happens in hormone signalling pathways

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

____are utilized for signals soluble in the aqueous extracellular environment. In this situation, the signal does not actually enter the cell but instead transmitted into the cell by receptors

A

cell surface receptors

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

What are the two major mediators of cell signalling?

A

protein phosphorylation
monomeric GTPases

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

Kd=
Can be used to measure the ____
This is important as most receptors can bind to multiple signals

A

dissociation constant
the affinity of a signal(ligand) for a receptor

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

G proteins require

A

GPCR(G-protein coupled receptor) and is mediated by heterotrimeric G protein (GTP-binding protein)

cell surface receptor

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

What are GPCR’s

A

are seven-transmembrane receptors that activate heterotrimeric GTPases by exchanging the GDP for GTP in the alpha subunit. This causes the alpha subunit to separate from beta/gamma. Both can mediate downstream signalling but alpha is most predominantly

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

The fight or flight response is a good example of

A

GPCR signalling

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

Explain fight or flight

A

beta-adrenergic receptors( or glucagon) bind to epinephrine activating Gas which goes on to activate adenylyl cyclaces leading to production of cAMP

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

What is cAMP?

A

is a secondary messenger but most of its effected are mediated through PKA(protein kinase A)

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

Four types of cell surface receptors?

A

ION-Channel Ex.neurotransmitter gated ion channel
G-protein coupled receptors ex. Rhodopsin/Transducin
Enzyme-coupled ex.RTK
Nuclear receptor ex. steroid hormones

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

GTP hydrolysis is?

A

GTP to GDP turning off

17
Q

Heterotrimeric G-proteins are ___different components. When alpha subunit is bound by GDP it associates with betaY and is___

A

3
alpha beta
Y

inactive

18
Q

GEF

A

guanine nucleotide-exchange factors

19
Q

GPCR acts as a ____when stimulated by its ligand which exchange GDP for GTP on the alpha subunit

A

GEF

20
Q

cAMP(cyclic adenosine monophosphate) activates a protein kinase called?

A

PKA(protein kinase A)

21
Q

Protein kinase A is composed for two___ and two___. Regulatory subunit inhibits the ___in the absence of cAMP. When cAMP attached to regulator genes it detaches from catalytic and now they are activated to phosphorlate target proteins

A

regulatory subunits and catalytic subunits
catalytic

22
Q

How can PKA regulate gene expression?

A

cAMP stimulates PKA which binds CREB to CRE by phosphorylation this activates transcription and CBP binds to CREB

23
Q

inositol-1,4,5,-trisphosphate and diacylgycerol are

A

secondary messengers

24
Q

Calmodulin

A

involved in Ca+ signalling and is a highly conserved single polypeptide with 4 high affinity Ca+ sites

10 fold in Ca+ leads to a 50 fold in calmodulin

binds to other proteins and activates
Calmodulin changes conformation when Ca2+ is bound and can regulate a number of different protein targets

25
Q

Receptor tyrosine kinases

A

Epidermal growth factor receptor (EGF) is not activate without P but once EGF binds to receptor it pulls another structure towards itself multimerization….then it trans-autophorylation each other

26
Q

WHen tyrosine kinase is activated it also activates ___indirectly

A

Ras by Sos

27
Q

MAP Kinase pathway?

A

MAP=mitogen activated protein
mitogen are growth signals

Three comments MAPK, MAPKK, MAPKKK

Ras and Raf are connected and activate MAPKKK

Ets and Jun are the MAPS-they activate transcription

28
Q

Insulin pathway?

A

Insulin goes on receptor(alpha) goes through PM(beta) this phosphorylats IRS-1( which is the MAP kinase pathway), IRS-1 activates P1 3 kinase which catalyze an addition of a phosphate to PIP2 into PIP3. PTEN can covert PIP# back into PIP2. Then PIP3 binds to Akt which can increase glycogen synthase activity and recruit GLUT4.