Brainscape's Knowledge GenomeTM

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


See full index

BIOL 432 > Surface Receptors > Flashcards

Surface Receptors Flashcards

1
Q

four main types of surface receptors based on structure/function

A
  1. 7 transmembrane domain
  2. growth factor receptors
  3. cytokine receptors
  4. guanylyl cyclase receptors
    (5.) novel cell surface receptor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

GPCR N terminus

A

extracellular domain
- recognizes and binds to ligand, causes conformational change

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

GPCR C terminus

A

intracellular domain
- c terminus; hydrophilic; transduce signal via G proteins (interacts w G protein timer, always in cytosol)

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

what are the 7 hydrophobic segments that span the membrane of GPCR’s also called

A

serpentine receptors

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

GPR disease

A

Mutations in G protein receptors important
pathology in endocrine disorders; often need
homozygous mutation to have loss of function
since excess receptors; also, could have gain of
function, if mutation causes constitutive activation; a single point mutation may also alter binding specificity or receptor desensitization

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

pindolol

A

is a nonselective beta blocker
- receptor antagonist

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

iodocyanopindolol

A

is a b1 adrenoreceptor antagonist and a serotonin receptor antagonist

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

Gαs-AC Coupled Signaling step 1

A

1) Epinephrine binds
β-adrenergic
receptor with Gαs

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

Gαs-AC Coupled Signaling step 2

A

2) AC activated to produce cAMP

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

Gαs-AC Coupled Signaling step 3

A

3) cAMP binds to inhibitory
subunit of protein kinase A
(PKA) and releases enzyme

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

Gαs-AC Coupled Signaling step 4

A

4) PKA phosphorylates substrates

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

Gαs-AC Coupled Signaling step 5

A

5) CREB = cAMP response

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

Specific Disease of G Protein

A

Specific Disease of G Protein
Signalling: Cholera toxin
(bacterium Vibrio cholerae) blocks
GTPase activity of alpha subunit
and so cAMP stimulation constant

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

__ binds to consensus
___ in basal state, but when
____ is activated
to enhance transcription

A

CREB binds to consensus
CRE in basal state, but when
phosphorylated is activated
to enhance transcription

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

GTP

A

= guanosine triphosphate

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

GDP

A

GDP= guanosine diphosphate + free phosphate
(Pi = inorganic phosphate)

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

G proteins

A
  • Heterotrimers, subunits = αβγ
  • G-proteins identified by the α-subunit
    – αs = stimulation of AC
    – αi = inhibition of AC
    – αq/11 = stimulation of PLC
  • α-subunit has GTPase activity
  • β/γ act as a dimer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

G protein Signaling General Mechanism step 1

A

1) Inactive complex
(associated
with receptor in
membrane)

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

G protein Signaling General Mechanism step 2

A

2) Ligand binds inducing
conformation change in
receptor

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

G protein Signaling General Mechanism step 3

A

3) Receptor-G protein
complex forms and
GDP dissociates from
alpha subunit

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

G protein Signaling General Mechanism step 4

A

4) GTP binds (GTP 10x>GDP in cytosol)

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

G protein Signaling General Mechanism step 5

A

5) Gα-GTP dissociate
from receptor and
beta/gamma subunits

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

G protein Signaling General Mechanism step 6a

A

6a) Gα-GTP act on effectors
(depends on alpha subtype
e.g. PLC, AC)

24
Q

G protein Signaling General Mechanism step 6b

A

6b) beta/gamma may

also act on effectors

25
Q

G protein Signaling General Mechanism step 7

A

7) Intrinsic GTPase of alpha

converts GTP to GDP

26
Q

G protein Signaling General Mechanism step 8

A

8) Subunits reassociate

27
Q

G protein Signaling General Mechanism Regulated by..

A

a) GPR-associated protein (GAP) helps
inactivate Gα-GTP and acts as scaffold for assembly
b) Receptor desensitization (βadrenergic receptor kinase and arrestin)

28
Q

αs Stimulatory (esp. AC) effector

A

adenylyl cyclase
ca channels
k channels

29
Q

ai Inhibitory effector

A

adenylyl cyclase
ca channels
k channels

30
Q

aq Stimulates PLC effector

A

PLCb

Other ligands for GPCR using alpha q – Angiotensin II,
Bradykinin, Acetylcholine

31
Q

Phosphatidylinositol (4,5)-bisphosphate

A

(PtdIns(4,5)P2 or PIP2 ) is a minor
phospholipid component of cell membranes. PtdIns(4,5)P2 is enriched at the plasma membrane where it is an important substrate for a number of important signalling proteins. Phospholipase C hydrolyzes the phosphodiester link in PtdIns(4,5)P2 forming inositol 1,4,5-triphosphate (InsP3) and diacylglycerol (DAG).

32
Q

IP3

A

IP3 = inositol
triphosphate
(2nd messenger)

33
Q

DAG

A

DAG =
diacylglycerol
(2nd messenger)

34
Q

Gq-PLC-coupled Signaling

step 1

A

1) Ligand (e.g. Angiotensin II)

binds receptor with Gαq

35
Q

Gq-PLC-coupled Signaling

step 2a

A

2a) Phospholipase cleavage: PIP2
to IP3 (2nd messenger) causing
release of calcium (2nd messenger)
to cytoplasm from the ER and also
forms DAG (2nd messenger)

36
Q

Gq-PLC-coupled Signaling

step 2b

A

2b) DAG may come
directly from
phosphatidylcholine
cleavage

37
Q

Gq-PLC-coupled Signaling

step 3a

A

3a) calcium activates protein
kinases, promotes secretion,
causes contraction

38
Q

Gq-PLC-coupled Signaling

step 3b

A

3b) DAG second messenger

activates protein kinase C

39
Q

Gq-PLC-coupled Signaling

step 4

A

4) PKC numerous
substrates, some of which
involve transcription effects
in the nucleus

40
Q

Desensitization of the β-adrenergic receptor in G protein Signalling
step 1

A

1) Activation of receptor and AC

41
Q

Desensitization of the β-adrenergic receptor in G protein Signalling
step 2

A

2) Phosphorylation of receptor by
β-adrenergic receptor kinase
βARK , a GRK (G proteincoupled receptor kinase)

42
Q

Desensitization of the β-adrenergic receptor in G protein Signalling
step 3

A

3) Inactive AC; arrestin
binds when Pylated and
blocks association with
G protein

43
Q

Desensitization of the β-adrenergic receptor in G protein Signalling
step 4

A

4) Phosphatase removes phosphate
from receptor, allows G protein
association and activation of AC

44
Q

cholera toxin – (also known as choleragen and sometimes
abbreviated to CTX, Ctx or CT) is protein complex secreted
by the bacterium Vibrio cholerae. It causes …..

A

ADP-ribosylation
of Gαs = inhibits GTPase activity – AC active longer
– In gut = increase water and salt secretion

45
Q

pertussis toxin is a protein-based AB5-type exotoxin
produced by the bacterium Bordetella pertussis – it also
causes…..

A

ADP-ribosylation of Gαi & Gαo prevents G protein
binding HR – inactive GDP-bound G protein

46
Q

Genetic disorders in α subunits

– Eg. Pseudohypoparathyroidism type Ia (PHP-Ia)

A

Target cell resistance to PTH, with ↑ [PTH]

47
Q

In Growth Factor Receptors enzyme tyrosine kinase is part of receptor (2)

A

1) adds phosphate to substrates that recruit other proteins
= signaling complexes

2) adds phosphate to proteins that are also kinases
= phosphorylation cascades

48
Q

Growth Factor Receptors - Signaling Complexes

Step 1

A

1) Typically dimers form upon
ligand binding (but not
shown here)

49
Q

Growth Factor Receptors - Signaling Complexes

Step 2

A

2) Autophosphorylation

50
Q

Growth Factor Receptors - Signaling Complexes

Step 3

A

3) recruitment of accessory
proteins (SH2 domains
recognize phosphorylated
tyrosines; SH3 domains
recognize proline rich
sequences)

51
Q

Growth Factor Receptors - Signaling Complexes

Step 4

A

4) SH3 proteins also have Tyr phosphorylation

52
Q

Growth Factor Receptors - Signaling Complexes

Step 5

A

5) Very large complexes may form with complicated signalling

53
Q

SH2

A

– src homology domain (type 2)

54
Q

SH3

A

sh3 type 3

55
Q
A

BIOL 432 (19 decks)

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