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Intracellular messenger substances:
second messengers
Min-Chuan Huang
[email protected]
1
Types of second messengers
• Cytosolic:
– cAMP, cGMP, cGMP-AMP (Science. 2013 Feb
15;339:826)
– Inositol phosphates
– Ca2+
• Membrane-associated
– DAG
– phosphatidylinositides
• Gases:
– NO, CO, H2S
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Intracellular messenger substances:
second messengers
Gases:
NO
CO
H2S
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modified from Biochemistry of Signal Transduction and Regulation. 2008.
4th
ed. Gerhard Kraus
cAMP
Earl Wilbur Sutherland Jr.
Nobel Prize in Physiology or Medicine
in 1971
phosphodiesterase
adenylyl cyclase
H2 O
ATP
cAMP
AMP
epinephrine
β-Adrenergic receptor
4
NATURE REVIEWS | MOLECULAR CELL BIOLOGY VOLUME 3 | SEPTEMBER 2002 | 639-650
Adenylyl cyclases
(transmembrane and soluble ACs)
Molecular Cell Biology, 2013. 7th ed. Lodish
• 10 known adenylate cyclases in mammals:
ADCY1 -9 (transmembrane), ADCY10 (soluble)
• tmAC: regulated by Gα, Gβγ, Ca2+
• sAC: regulated by HCO35
Transmembrane (tm)AC and soluble (s)AC
HCO3-
Kidney International (2011) 79, 1277–1288
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Targets of cAMP
1. PKA
2. cAMP-specific
phosphodiesterases (PDEs)
3. Ion channels
4. Epac : GEF for Rap
Epac: Exchange protein directly activated by cyclic AMP
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Targets of cAMP
1.
3.
2.
4.
Pharmacol Rev. 2013 Feb 27;65(2):670-709.
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cAMP activates PKA
PKA
9
Biochemistry of Signal Transduction and Regulation.
4th
ed. Gerhard Kraus
Epac is cAMP-dependent GEF for Rap
Br J Pharmacol. 2010 Jan 1;159(2):265-84.
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cGMP
• Guanylyl cyclase synthesizes cGMP from GTP.
• Two groups of guanylyl cyclases:
– Guanylyl cyclase receptors
– soluble guanylyl cyclases
• Phosphodiesterase degrades cGMP to GMP.
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Guanylyl cyclase receptors
• Activated by extracellular
peptide ligands: atrial
natriuretic peptide
• Single transmembrane
protein
• Synthesize cGMP in an ATPdependent manner
12
Biochemistry of Signal Transduction and Regulation.
4th
ed. Gerhard Kraus
Soluble guanylyl cyclases
β subunit
Trends Biochem Sci. 2006 Apr;31(4):231-9.
• Contain a heme group
• Activated by NO (NO receptor)
• Active form: heterodimer (α+β). In humans, it is
encoded by the genes GUCY1A2, GUCY1A3, GUCY1B2 and
GUCY1B3
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NO receptor = soluble guanylyl cyclase (sGC)
14
Molecular Cell Biology, 2013. 7th ed. Lodish
Targets of cGMP
• PKG
• cGMP-gated cation channels
• cAMP-dependent PDEs
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peptide
PDE
HCO3-
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modified from Biochemistry of Signal Transduction and
Regulation. 4th
ed. Gerhard Kraus
Cyclic GMP-AMP (cGAMP)
cGAMP synthase (cGAS)
Science. 2013 Feb 15;339:826
Science. 2013 Feb 15;339:786
stimulator of interferon
genes (STING)
Science 339, 763 (2013)
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Phosphatidylinositol-derived
messengers
•
•
•
•
•
DAG
IP3
IPx
PI(3,4,5)P3
PIPx
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19
Molecular Cell Biology, 2008. 6th ed. Lodish
Key enzymes of PtdIns metabolism
• PLCβ and PLCγ
• PI3K
• Phosphoinositide phosphatases
20
RTK vs. GPCR
Gq
PLCγ vs. PLCβ
21
Biochemistry of Signal Transduction and Regulation.
4th
ed. Gerhard Kraus
22
Molecular Cell Biology, 2013. 7th ed. Lodish
23
Molecular Cell Biology, 2013. 7th ed. Lodish
(Akt)
(Akt)
(Akt)
PDK2
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Molecular Cell Biology, 2013. 7th ed. Lodish
25
Biochemistry of Signal Transduction and Regulation.
4th
ed. Gerhard Kraus
DAG as a signal molecule
- Formed from PIP2
- Activates PKC
- Source of arachidonic acid
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Biochemistry of Signal Transduction and Regulation.
4th
ed. Gerhard Kraus
Other lipid messengers
•
•
•
•
•
Ceramide
Sphingosine-1-phosphate (S1P)
Lysophosphatidic acid (LPA)
Platelet activating factor (PAF)
Arachidonoyl ethanolamine (AEA)
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Ca2+ as a signal molecule
•
•
•
•
•
•
•
Muscle contraction
Vision process
Cell proliferation
Secretion
Cell motility
Formation of cytoskeleton
Gene expression
28
Storage and release of Ca2+
10-3 M
10-7 - 10-8 M
29
Biochemistry of Signal Transduction and Regulation.
4th
ed. Gerhard Kraus
Ryanodine receptors and IP3 receptors
Ryanodine receptor
Ryanodine receptor
Skeletal muscle
Biochemistry of Signal Transduction and Regulation.
Cardiac muscle
4th
ed. Gerhard Kraus
IP3 receptor
30
Opening of Ryanodine receptors and IP3 receptors by:
IP3, Ca2+, cADP ribose, NAADP
Biochemistry of Signal Transduction and Regulation.
4th
ed. Gerhard Kraus
cADPR
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2+
Ca
release
32
Biochemistry of Signal Transduction and Regulation.
4th
ed. Gerhard Kraus
How Ca2+ works?
• Direct activation of enzymes
– PKC
– PLA2
– PLCγ
• Binding to Ca2+ sensors
– Calmodulin
– Troponin C
– Recoverin
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Mechanisms of activation of target proteins by
Ca2+ / calmodulin
... .. --. -. .- .-.. /
- .-. .- -. ... -.. ..- .-. - .. --- -.
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Biochemistry of Signal Transduction and Regulation.
4th
ed. Gerhard Kraus
NO as a signaling molecule
The Nobel Prize in Physiology or Medicine in 1998 :
Ferid Murad, Robert F. Furchgott, and Louis Ignarro
Soluble guanylyl cyclase
Hb
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NATURE REVIEWS | MOLECULAR CELL BIOLOGY VOLUME 6 | FEBRUARY 2005 | 151
NO-sensitive guanylyl cyclase
Handb Exp Pharmacol. 2009;(191):17-31.
36
S-nitrosylation
37
Circ Res. 2010 Mar 5;106(4):633-46.
Protein denitrosylation:
Trx/TrxR and GSH/GSNOR systems
Nat Rev Mol Cell Biol. 2009 Oct;10(10):721-32.
38
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Nature Reviews Molecular Cell Biology 10, 721-732 (October 2009)
Aberrant S-Nitrosylation in Cardiovascular Disease
SNO Protein
Serum albumin
Hb
HIF-1
Matrix metalloproteinase 9
Ryanodine receptor 2
L-type Ca2+ channel (1C subunit)
Cardiac Na+ channel SNC5a
Slowly activating delayed-rectifier
K+ channel
Insulin receptor β
Insulin receptor substrate 1
Akt (protein kinase B)
Disease State
Preeclampsia
Ischemic coronary syndromes
Congestive heart failure
Pulmonary arterial hypertension
Sickle cell disease
Diabetes (type 1)
Septic shock
Pulmonary arterial hypertension
Stroke
Arrhythmogenesis, Heart failure
Atrial fibrillation/arrhythmia
Long Q/T syndrome
Atrial fibrillation/arrhythmia
Diabetes (type 2)
Diabetes (type 2)
Diabetes (type 2)
40
Circ Res. 2010 Mar 5;106(4):633-46.
Interactions between the three gasgenerating systems
Haem oxygenase 1
Nat Rev Drug Discov. 2010 Sep;9(9):728-43.
41
Major sites of reactive oxygen species (ROS)
(superoxide)
42
Nat Rev Drug Discov. 2009 Jul;8(7):579-91.
Mechanisms of ROS effects on protein functions
43
Nat Rev Drug Discov. 2009 Jul;8(7):579-91.