Signal Transduction:
Dopamine Signaling
Outline
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•
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Dopamine and dopamine receptors
cAMP-PKA pathway
PLC pathway
Regulation of ion channel by dopamine
Early signal quench and late signal induction
Dopamine
• Neurotransmitter in Central Neural System
• Neurohormone in periphery
• important roles in behavior and cognition,
voluntary movement, motivation, sleep, mood,
attention, working memory, and learning
http://www.3dchem.com/molecules.asp?ID=289
Synapse in CNS
http://blog.lib.umn.edu/trite001/studyinghumananatomyandphysiology/2008/04/dopamine_excitatory_or_inhibit.html
Dopamine signaling related disease
• Tourette’s syndrome, schizophrenia, and drug
and alcohol abuse, Parkinson’s disease etc.
• depending on the site of their neurobiological
correlate
http://www.willamette.edu/~gorr/classes/cs449/brain.html
G-protein Coupled receptors
• Ligand binding
• changing in
receptor
conformation
• Facilitate
release of GDP
and binding of
GTP
http://openwetware.org/wiki/BIO254:Gprotein
Recall: classfication
Class A (Rhodopsin family)
- Highly conserved amino acids (red circles)
- Disulphide bridge connecting E1 & E2
- Palmitoylated cysteine in the C-terminal tail
- Tilted or kinked due to presence of P’s in TMD’s
Class B (Secretin & Adhesion families)
- Relatively long N- terminus w/ disulphide cysteine
bridges
- No palmitoylation site
- Conserved residues and motifs (different from A)
Class C (Glutamate family)
- Long N-terminus and C-tail
- Ligand-binding domain (yellow) in N- terminus
forms disulphide-linked dimer
- 2 cys in E1 & E2 form putative disulphide bridge
- C1 is short & highly conserved
http://www.gpcr.org/7tm/phylo/phylo.html
Dopamine Receptors
• Class -A : Rhodopsin
family
• D1-like Family:
D1 D5
• D2-like Family:
D2, D3, and D4
• Grouped by similarity
of signal pathways &
structure
• Two families can have
“cross talk”
Receptor Structure
• D3 receptor (homo sapiens)
400 aa
ECL2 forms ligand
binding pocket
(Ellen Chien, 2010)
LCL2 is transient,
raising the
possibility
that interactions
between ICL2 and
the receptor
ionic lock
Outline
•
•
•
•
•
Dopamine and dopamine receptors
cAMP-PKA pathway
PLC pathway
Regulation of ion channel by dopamine
Early signal quench and late signal induction
D1&D2 signaling overview
(KA Neve, 2004)
D1&D2 signaling overview
(KA Neve, 2004)
Recall: Families of G
Family Gene
Varients
Gs
Gi
Effectors
2nd
Association
Messenger
s(S), s(L)
 adenylyl cyclase cAMP
olf
 adenylyl cyclase cAMP
i1,i2,i3,
 adenylyl cyclase cAMP
0a, 0b
 phospholipaseC IP3, DAG
Brain
t1, t2
cGMP-PDE
Retina
gust
 phospholipaseC IP3, DAG
z
 adenylyl cyclase cAMP
cGMP
Gq
q,11,14,  phospholipaseC IP3, DAG
15, 16
G12
12, 13
 Rho-GEF
Olfactory
Gustatory
Rho
Adapted from Beckerman, Molecular & Cellular Signaling
cAMP-PKA pathway
D1-like receptor
D2-like receptor
Gαs
Gαi/0
Adenylyl Cyclase 5
cAMP
CREB
PKA
PP2A (protein phosphatase)
De-P on Thr 75
DARPP-32(PP1 R1B)
P on Thr 34
Alberts MBoC, Fig 15-36, 5th ed.
PP1
Channel/
transporter
Protein phosphatase
Protein Phosphatase 2A
Protein Phosphatase 1
Catalytic subunit
scaffolding subunit
(Y Xu, 2006)
regulatory subunit
(A hirschi,2010)
cAMP-PKA pathway is in crosstalk
and regulated
Epac
MAPK Kinase
MAP Kinase
(JM beaulieu,2011)
MAPK
(JM beaulieu,2011)
Outline
•
•
•
•
•
Dopamine and dopamine receptors
cAMP-PKA pathway
PLC pathway
Regulation of ion channel by dopamine
Early signal quench and late signal
D1-like receptor activate Gq
Family Gene
Varients
Gs
Gi
Effectors
2nd
Association
Messenger
s(S), s(L)
 adenylyl cyclase cAMP
olf
 adenylyl cyclase cAMP
i1,i2,i3,
 adenylyl cyclase cAMP
0a, 0b
 phospholipaseC IP3, DAG
Brain
t1, t2
cGMP-PDE
Retina
gust
 phospholipaseC IP3, DAG
z
 adenylyl cyclase cAMP
cGMP
Gq
q,11,14,  phospholipaseC IP3, DAG
15, 16
G12
12, 13
 Rho-GEF
Olfactory
Gustatory
Rho
Adapted from Beckerman, Molecular & Cellular Signaling
D1 family-PLC pathway
PKC
(JM beaulieu,2011)
Alberts, MBoC, Fig 15-39, 5th ed.
D2-like receptor activate via Gβγ
adenylyl cyclase
ion channels
phospholipases
kinases
guanine nucleotide exchange factor
kinases
 binding protein
NATURE REVIEWS | DRUG DISCOVERY
604| JULY 2004 | VOLUME 3
D2 family-PLC pathway
(JM beaulieu,2011)
Outline
•
•
•
•
•
Dopamine and dopamine receptors
cAMP-PKA pathway
PLC pathway
Regulation of ion channel by dopamine
Early signal quench and late signal induction
RECALL
Four Families of Ion Channels
Ion Channel
Selectivity
Voltage-gated
6TM cation
Calcium
Ca2+
HCN
Na+, K+
Potassium
K+
Sodium
Na+
Voltage-gated ion
ClC
Channel assembly
6TM, loop
24 TM, 4 loops
Tetrameric,
Monomeric
10-18IM
Dimeric
4TM
Pentameric
3TM, loop
Tetrameric
Cl-
Cys-loop receptor
Ligand-gated
Subunit Topology
nAChR
Cations
GABAA,C
Anions (Cl-)
Glycine
Anions (Cl-)
5-HT3
Cations
Glutamate recep’r
AMPA
Na+, K+
Kainate
Na+, K+
NMDA
Ca2+
Overview of ion channel regulated
(KA Neve, 2004)
Dopamine regulated K+ channels
• G protein-regulated inwardly rectifying K+
channels (GIRK)
D1 receptor PKA
GIRK
D2 receptor PKA
GIRK
• voltage-gated K+ channels (VGKC)
Iks/IA/ID
PKA
D1 receptor
VGKC
PKA
D2 receptor
VGKC
Gbγ
Dopamine regulated Ca2+ channels
• Voltage gated calcium Channel
PKA/PKC
D1 receptor
L-type channel
PKA
N,P/Q type channel
D2 receptor Gbγ
L,N,P/Q type of channel
Dopamine regulated Na+ channels
• Voltage gated Na+ Channel (INat and INap)
• D1 receptor PKA pathwayα-subunit Ser
573 phosphorylation
transient Na+
PKA/PKC
• current D1 receptor
persistent Na+
current
PKA inhibition
• D2 receptor
Na+ channels
Gbγ
Dopamine regulated glutamate
receptors
• D1 receptor
• D2 receptor
NMDA
AMPA
GABA
PKA
PKA inhibition/
?
Gbγ
Gbγ
NMDA
AMPA
GABA
Direct interaction between DA
receptor and ion channels
-- D1 receptor
-- D1 receptor
PKA
D2 receptor
D5 receptor
N-type Calcium Channels
NMDA
NMDA
GABA
Outline
•
•
•
•
•
Dopamine and dopamine receptors
cAMP-PKA pathway
PLC pathway
Regulation of ion channel by dopamine
Early signal quench and late signal induction
DA receptor early signal shutdown &
late signal induction
(JM beaulieu,2011)
RGS deactivate Gα
RGS 9-2
regulates D2like receptor
signaling
Probably
cooperate with
RGS 7,
mediated by
R7BP
GRK deactivate GPCR
• GPCR Kinase
• 3 families:
• GRK1 like (1 and 7)
retina specific
1  rhodopsin
7 iodopsin
• GRK2-like (2 and 3)
• GRK4-like (4,5 and 6)
GRK
Arrestin and downstream pathway
• arrestin 1 (rod)
arrestin 4 (cone)
β-arrestin 1 2 (widely)
β-arrestin 2 (widely)
• Binds phosphorylated GRK
1.Recruit Clathrininternalizationrecycle or degrade GPCR
2.Scaffold PP2A and Akt(PKB)  dephosphorylate (deactivate)Akt
http://www.fz-juelich.de/isb/isb-2/topics/arrestin
Akt activation pathway
mTOR
http://www.nature.com/onc/journal/v24/n50/fig_tab/1209099f1.html
Glycogen synthase
kinase 3 (GSK-3) is
a serine/threonine
protein kinase
NMDA
AMPA
(JM beaulieu,2011)
Summary
• D1 and D2 families of dopamine receptor have
distinct effect on cAMP-PKA pathway, but also
share similar effect in PLC pathway
• D1 and D2 families have different effect on
regulation of ion channels
• Dopamine receptor signal can be shut down
and induce late signal(Akt pathway)
Reference
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Beaulieu, J. M. and R. R. Gainetdinov (2011). "The Physiology, Signaling, and Pharmacology of Dopamine
Receptors." Pharmacological Reviews 63(1): 182.
Cave, J. W. and H. Baker (2009). "Dopamine systems in the forebrain." Development and Engineering of
Dopamine Neurons: 15-35.
Chien, E. Y. T., W. Liu, et al. (2010). "Structure of the human dopamine D3 receptor in complex with a D2/D3
selective antagonist." Science 330(6007): 1091.
Hirschi, A., M. Cecchini, et al. (2010). "An overlapping kinase and phosphatase docking site regulates activity
of the retinoblastoma protein." Nature structural & molecular biology
Kienast, T. and A. Heinz (2006). "Dopamine and the diseased brain." Current Drug Targets-CNS &# 38;
Neurological Disorders 5(1): 109-131.
Kurachi, Y. and M. Ishii (2004). "Cell signal control of the G protein-gated potassium channel and its
subcellular localization." The Journal of Physiology 554(2): 285.
Lüscher, C. and P. A. Slesinger (2010). "Emerging roles for G protein-gated inwardly rectifying potassium
(GIRK) channels in health and disease." Nature Reviews Neuroscience 11(5): 301-315.
Missale, C., C. Fiorentini, et al. (2010). "The neurobiology of dopamine receptors: evolution from the dual
concept to heterodimer complexes." Journal of Receptors and Signal Transduction 30(5): 347-354.
Neve, K. A., J. K. Seamans, et al. (2004). "Dopamine receptor signaling." Journal of Receptors and Signal
Transduction 24(3): 165-205.
Xu, Y., Y. Xing, et al. (2006). "Structure of the protein phosphatase 2A holoenzyme." Cell 127(6): 1239-1251.