intracellular messenger substances: second messengershomepage.ntu.edu.tw/~mchuang/second...

Min-Chuan Huang

mchuang@ntu.edu.tw

1

Intracellular messenger substances: second messengers

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 2

Intracellular messenger substances: second messengers

3 modified from Biochemistry of Signal Transduction and Regulation. 2008. 4th ed. Gerhard Kraus

Gases: NO CO H2S

cAMP

4

adenylyl cyclase phosphodiesterase

H2O

cAMP ATP AMP

Earl Wilbur Sutherland Jr. Nobel Prize in Physiology or Medicine

in 1971

β-Adrenergic receptor epinephrine

NATURE REVIEWS | MOLECULAR CELL BIOLOGY VOLUME 3 | SEPTEMBER 2002 | 639-650

Adenylyl cyclases (transmembrane and soluble ACs)

• 10 known adenylate cyclases in mammals: ADCY1 -9 (transmembrane), ADCY10 (soluble)

• tmAC: regulated by Gα, Gβγ, Ca2+

• sAC: regulated by HCO3-

5

Molecular Cell Biology, 2013. 7th ed. Lodish

Transmembrane (tm)AC and soluble (s)AC

6 Kidney International (2011) 79, 1277–1288

HCO3-

Targets of cAMP 1. PKA

2. cAMP-specific phosphodiesterases (PDEs)

3. Ion channels

4. Epac : GEF for Rap

7

Epac: Exchange protein directly activated by cyclic AMP

8 Pharmacol Rev. 2013 Feb 27;65(2):670-709.

Targets of cAMP

1.

2.

3.

4.

9

PKA

cAMP activates PKA

Biochemistry of Signal Transduction and Regulation. 4th ed. Gerhard Kraus

Epac is cAMP-dependent GEF for Rap

10 Br J Pharmacol. 2010 Jan 1;159(2):265-84.

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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• Activated by extracellular peptide ligands: atrial natriuretic peptide

• Single transmembrane protein

• Synthesize cGMP in an ATP-dependent manner

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Guanylyl cyclase receptors

Biochemistry of Signal Transduction and Regulation. 4th ed. Gerhard Kraus

Soluble guanylyl cyclases

• 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 13

Trends Biochem Sci. 2006 Apr;31(4):231-9.

β subunit

Molecular Cell Biology, 2013. 7th ed. Lodish

NO receptor = soluble guanylyl cyclase (sGC)

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Targets of cGMP

• PKG

• cGMP-gated cation channels

• cAMP-dependent PDEs

15

16 modified from Biochemistry of Signal Transduction and Regulation. 4th ed. Gerhard Kraus

peptide

PDE

HCO3-

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Cyclic GMP-AMP (cGAMP) cGAMP synthase (cGAS)

Science. 2013 Feb 15;339:826 Science. 2013 Feb 15;339:786

Science 339, 763 (2013)

stimulator of interferon genes (STING)

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

21

RTK vs. GPCR PLCγ vs. PLCβ

Biochemistry of Signal Transduction and Regulation. 4th ed. Gerhard Kraus

Gq

22 Molecular Cell Biology, 2013. 7th ed. Lodish

23 Molecular Cell Biology, 2013. 7th ed. Lodish

24

(Akt) PDK2 (Akt) (Akt)

Molecular Cell Biology, 2013. 7th ed. Lodish

25 Biochemistry of Signal Transduction and Regulation. 4th ed. Gerhard Kraus

DAG as a signal molecule

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- Formed from PIP2 - Activates PKC - Source of arachidonic acid

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

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Storage and release of Ca2+

29 Biochemistry of Signal Transduction and Regulation. 4th ed. Gerhard Kraus

10-3 M

10-7 - 10-8 M

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Ryanodine receptors and IP3 receptors

Skeletal muscle Cardiac muscle Biochemistry of Signal Transduction and Regulation. 4th ed. Gerhard Kraus

Ryanodine receptor

Ryanodine receptor IP3 receptor

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Opening of Ryanodine receptors and IP3 receptors by: IP3, Ca2+, cADP ribose, NAADP

Biochemistry of Signal Transduction and Regulation. 4th ed. Gerhard Kraus cADPR

Ca2+ 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 33

Mechanisms of activation of target proteins by Ca2+ / calmodulin

34 Biochemistry of Signal Transduction and Regulation. 4th ed. Gerhard Kraus

... .. --. -. .- .-.. / - .-. .- -. ... -.. ..- -.-. - .. --- -.

35

NO as a signaling molecule

NATURE REVIEWS | MOLECULAR CELL BIOLOGY VOLUME 6 | FEBRUARY 2005 | 151

Soluble guanylyl cyclase Hb

The Nobel Prize in Physiology or Medicine in 1998 : Ferid Murad, Robert F. Furchgott, and Louis Ignarro

NO-sensitive guanylyl cyclase

36 Handb Exp Pharmacol. 2009;(191):17-31.

37 Circ Res. 2010 Mar 5;106(4):633-46.

S-nitrosylation

Protein denitrosylation:

38

Trx/TrxR and GSH/GSNOR systems

Nat Rev Mol Cell Biol. 2009 Oct;10(10):721-32.

39 Nature Reviews Molecular Cell Biology 10, 721-732 (October 2009)

40

SNO Protein Disease State Serum albumin Preeclampsia

Ischemic coronary syndromes Hb Congestive heart failure

Pulmonary arterial hypertension Sickle cell disease Diabetes (type 1) Septic shock

HIF-1 Pulmonary arterial hypertension Matrix metalloproteinase 9 Stroke Ryanodine receptor 2 Arrhythmogenesis, Heart failure L-type Ca2+ channel (1C subunit) Atrial fibrillation/arrhythmia Cardiac Na+ channel SNC5a Long Q/T syndrome Slowly activating delayed-rectifier K+ channel

Atrial fibrillation/arrhythmia

Insulin receptor β Diabetes (type 2) Insulin receptor substrate 1 Diabetes (type 2) Akt (protein kinase B) Diabetes (type 2)

Aberrant S-Nitrosylation in Cardiovascular Disease

Circ Res. 2010 Mar 5;106(4):633-46.

Interactions between the three gas-generating systems

41 Nat Rev Drug Discov. 2010 Sep;9(9):728-43.

Haem oxygenase 1

Major sites of reactive oxygen species (ROS)

42 Nat Rev Drug Discov. 2009 Jul;8(7):579-91.

(superoxide)

Mechanisms of ROS effects on protein functions

43 Nat Rev Drug Discov. 2009 Jul;8(7):579-91.