Manifestation of Novel Social Challenges of the European Union in the Teaching Material of Medical Biotechnology Master’s Programmes at the University of Pécs and at the University of Debrecen Identification number: TÁMOP-4.1.2-08/1/A-2009-0011 Manifestation of Novel Social Challenges of the European Union in the Teaching Material of Medical Biotechnology Master’s Programmes at the University of Pécs and at the University of Debrecen Identification number: TÁMOP-4.1.2-08/1/A-2009-0011

Tímea Berki and Ferenc Boldizsár G-PROTEIN-LINKED RECEPTORS TÁMOP-4.1.2-08/1/A-2009-0011 Nomenclature

• G-protein-coupled receptors (GPCRs) • Seven-transmembrane domain receptors • 7-TM receptors • Heptahelical receptors • Serpentine • G protein-linked receptors (GPLR)

TÁMOP-4.1.2-08/1/A-2009-0011 7-transmembrane-spanning receptors (7-TM)

N

N-Glycosylation (Receptor folding, trafficking)

EL1 EL2 EL3 Extracellular loops (EL1-3)

Plasma membrane Interaction surface

Ligand-binding

Gα C-terminal tail TM TM TM TM TM TM TM Transmembrane helix Gα -binding 1 2 3 4 5 6 7 (TM1-7) Other Gα surfaces

Helix 8 (Gβ-binding)

PKC phosphorylation (Desensitization) Intracellular loops (IL1-3) IL1 IL2 IL3 Palmitoylation E/DRY Motif (Lipid raft localization) GRK phosphorylation (Receptor activity and (Desensitization) protein-protein interactions) PKC phosphorylation (Desensitization) C TÁMOP-4.1.2-08/1/A-2009-0011 GPCR TÁMOP-4.1.2-08/1/A-2009-0011 Structure of 7-TM receptors

Inactive GPCR Active GPCR

Side perspective Agonist N EL 3 N

EL2 Intracellular loops EL1 TM TM 5 7 TM TM TM 6 TM 6 1 TM 7 5 TM TM 1 TM 3 C 2 TM C TM 4 TM 3 2 TM Gα 4

Extracellular loops IL3 Ga

IL 1 C-terminal IL2 tail of Ga Intracellular persective Non-covalent C bond C N N EL3 EL3 TM TM IL3 TM 6 IL3 7 TM 7 TM 6 TM Ga TM 1 TM Ga-binding 1 5 surface 5 TM TM EL2 IL1 IL1 TM 3 TM 3 TM EL2 TM 2 EL1 2 EL1 IL2 4 IL2 4 TÁMOP-4.1.2-08/1/A-2009-0011 GPCR subtypes

• Class A (or 1) – Rhodopsin-like • Class B (or 2) – family • Class C (or 3) – Metabotropic glutamate/pheromone • Class D (or 4) – Fungal mating pheromone receptors • Class E (or 5) – Cyclic AMP receptors • Class F (or 6) – Frizzeled/ TÁMOP-4.1.2-08/1/A-2009-0011 Activation of G-protein-coupled receptors (GPCR)

G-protein coupled receptor Signal molecule (GPCR)

a  a  a  b b b GDP GDP GTP Inactive G-protein

GDP GTP

Plasma membrane

 a  a Cytoplasm b b GTP GTP

Activated G-protein subunits TÁMOP-4.1.2-08/1/A-2009-0011 G-proteins

G-protein coupled receptor Plasma membrane (GPCR)

a  Cytoplasm b GDP

a  b GTP

Ion channels PI3K Phospholipases Gia Gsa Gqa G12/13a Adenylyl cyclases Receptor kinases GTP GTP GTP GTP

Adenylyl Adenylyl cyclase cyclase PLC ATP cAMP ATP cAMP PIP2 DAG Activates Rho

IP3 Phospholipases Ion channels Ca2+ TÁMOP-4.1.2-08/1/A-2009-0011 G-protein heterotrimer TÁMOP-4.1.2-08/1/A-2009-0011 Catecholamine hormon synthesis

+ + – + – H3N H3N CO2 H3N CO2 OH OH Tyrosine DOPA hydroxylase decarboxylase OH OH OH Tyrosine Dihydroxy Dopamine phenilalanine (L-DOPA) + H2 + H3N N

H3C OH OH Dopamine HO Phenethanolamine HO β-hydroxylase N-methyltransferase OH OH

Dopamine Epinephrine TÁMOP-4.1.2-08/1/A-2009-0011 Epinephrine and analogues

OH OH H NH OH H HO N 2 H N CH3 .HCL N CH3 .HCL CH3 .H2SO4 HO CH3 HO CH3 Tyramine HCL 2 Pseudoephedrine HCL Epinephrine (adrenaline) Ephedrine sulphate

OH NH2 NH2 NH2 .H2SO4 .H2SO4 .H2SO4 CH3 CH3 2 2 2 Amfetamine sulfate Dexamfetamine sulfate Phenylethanolamine sulfate

OH H OH HO N CH3 H OH .H SO H HO N CH3 2 4 CH3 N CH3 .HCL HO .H2SO4 CH CH 3 HO 3 OH CH3 2 HO Isoprenaline HCL 2 Orciprenaline sulfate Salbutamol sulfate

OH H HO N CH3

CH3 .H2SO4 CH3

OH 2 Terbutaline sulfate TÁMOP-4.1.2-08/1/A-2009-0011 cAMP-PKA pathway

Gα gated cAMP gated PO4 gated Receptor channel channel channel

a a Adenylyl a  cyclase b GTP GTP cAMP P P GTP ATP cAMP ADP

ATP cAMP R cAMP cAMP CREB R C cAMP R C C R C cAMP R C C cAMP cAMP R P Activated Inactive PKA cAMP CREB PKA

P CREB Gene expression

CRE Nucleus

cAMP Response Element TÁMOP-4.1.2-08/1/A-2009-0011 Primary Action of Epinephrine in a Liver Cell

Acetylcholine Epinephrine Stress signal Fuel for „fight or flight” Receptor

a  P s b Glucose Adenylate GDP Glucogen Cyclase Synthase Glucose-6- Phosphatase ATP cAMP Glucose-6-P Glucose-1-P Glycogen Fructose-2,6- P bisphosphatase Glucogen Phosphorylas Fructose-2,6-bisP Fructose-6-P e

Fructose-1,6- P PFK-1 bisphosphatase Phosphorylas Fructose-1,6- e bisP P Kinase A Protein Kinase A

PEP P

Pyr Kinase

Pyruvate TÁMOP-4.1.2-08/1/A-2009-0011 Glucagon signaling

Glucose low in blood Glucagon PANCREAS (Epinephrine) Receptor

a  P s b Glucose Adenylate GDP Glycogen Cyclase Synthase Glucose-6- Phosphatase ATP cAMP Glucose-6-P Glucose-1-P Glycogen Fructose-2,6- P bisphosphatase Glycogen Phosphorylas Fructose-2,6- Fructose-6-P e bisP Fructose-1,6- P PFK-1 bisphosphatase Fructose-1,6- bisP

Protein Kinase A

PEP P

Pyr Kinase

Pyruvate TÁMOP-4.1.2-08/1/A-2009-0011 Serotonin receptor

Serotonin receptor → G-protein → adenylyl cyclase → ATP → cAMP → PKA → cAMP Response Element (CRE) → Gene expression

TÁMOP-4.1.2-08/1/A-2009-0011 Types of serotonin receptor

Family Mechanism Potential 5-HT1 Decreasing cellular levels of cAMP Inhibitory 5-HT2 Increasing cellular levels of IP3 and DAG Excitatory 5-HT3 Depolarizing plasma membrane Excitatory 5-HT4 Increasing cellular levels of cAMP Excitatory 5-HT5 Decreasing cellular levels of cAMP Inhibitory 5-HT6 Increasing cellular levels of cAMP Excitatory 5-HT7 Increasing cellular levels of cAMP Excitatory TÁMOP-4.1.2-08/1/A-2009-0011 Receptor desensitization

Activated receptor Desensitized receptor

P P P P P P Arrestin ATP ADP GRK

G-protein linked receptor kinase