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

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

TYROSINE KINASE-

LINKED RECEPTORS PART 1

CYTOKINE-CHEMOKINE SIGNALING

Tímea Berki and Ferenc Boldizsár Signal transduction

at the University of Pécs and at the University of Debrecen

Identification number: TÁMOP-4.1.2-08/1/A-2009-0011

Cytokine groups

Structural:

1 4 a-helix bundle family

• IL-2 subfamily

• IFN subfamily

• IL-10 subfamily 2 IL-1 family

3 IL-17 family

Functional:

1 Haematopoietic (EPO, TPO, G-CSF, GM-CSF, SCF etc.) 2 Lymphocyte

differentiation/activation Th1: IL-2, TNF, IFNg

Th2: IL-4, IL-5, Il-13; IL-17, IL-23

3 Inflammatory (IL-1, IL-6, TNFa)

Cytokine receptors

Interferon-a, -β, and -g receptor, IL-10 receptor

Tumor necrosis factor (TNF) receptors I and II, CD40, Fas (Apo1, CD95), CD30, CD27, nerve growth factor receptor

CCR1-10, CXCR1-5, XCR1, CX3CR1

Receptor for IL-2, IL-4, IL-7, IL-9 and IL-15 share a common chain CD132 or

(common gamma chain).

Il-2 receptor also has a third chain, a high affinity subunit IL-2Ra (CD25)

Receptors for erythropoietin, growth hormone, and IL-13

Receptor for IL-3, IL-5, and GM-CSF share a common chain,CD131 or β

(common beta chain)

Class I cytokine receptor (hematopoietin receptor family)

Class II cytokine receptor

TNF-receptor family

Chemokine-receptor family

a β

Characteristics of multichain cytokine receptors

gp130 LIF/OSM

IL-6

gp130

IL-11

gp130

CNTF

CNTFR

gp130 GM-CSFRa

GM-CSF

β

IL-3R IL-3

β

IL-5R IL-5

β

IL-2Ra

IL-2Rβ IL-2

g

IL-2Rβ IL-15Ra

IL-15

g

IL-7R IL-7

g

IL-9R IL-9

g

IL-4R IL-4

g GM-CSF receptor subfamily

(common β subunit)

Il-6 receptor subfamily (common gp130 subunit)

Il-2 receptor subfamily (common g subunit)

Overview of cytokine signalling

Cytokine receptors consist of at least two chains, the cytoplasmatic domains of which bind Janus kinases

(JAKs)

JAK JAK

Transcription factors (STATs) bind to the phosphorylated receptors,

and are in turn phosphorylated by the

activated JAKs

Phosphorylated STATs form dimers that translocate into the nucleus

to initiate new gene transcription

JAK JAK

P P

P P JAK

JAK

P P

JAK JAK

Cytokine binding dimerizes the receptor, bringing together the cytoplasmic JAKs, which activate each

other and phosphorylate the receptor

JAK JAK

P P

P P

P P

P P

P P

STAT STAT

The structure of JAK and STAT proteins

FERM "SH

" yKI KI

JH7 JH6 JH5 JH4 JH3 JH2 JH1

0 200 400 600 800 1000 1200

NH

Coiled coil DBD Lk SH

Y TAD

P

0 200 400 600 800

JAK structure

STAT structure

JAK I

FERM "SH

" yKI KI

JH7 JH6 JH5 JH4 JH3 JH2 JH1

0 200 400 600 800 1000 1200

Kinase Pseudokinase

FERM domain:

band 4.1, ezrin, radixin and moesin

JH= Janus homology domain

Proline rich membrane proximal part of Cytokine

Receptors

JAK1 JAK2 JAK3 Tyk2

Y1038/Y1039 Y1007/Y1008 Y980/Y981 Y1054/Y1055

Activation Y residues:

JAK II

JAK 1 IFN-I/II, IL-2,-4,-6,-10 JAK2 IFN-II, IL-3,-5, GM-CSF JAK3 IL-2g,-4,-7,-9,-15,-21

TYK2 IFN-I, IL-6,-10,-12,-23

STAT I

NH

Coiled coil DBD Lk SH

Y TAD

P

0 200 400 600 800

DNA-binding

Transcriptional activation Linker

Receptor recruitment and dimerization Binding of regulators

Dimerization

DNA-binding

Nuclear transport

Human STATs

Name Chr (Hu) MW (kDa) Function Upstream

STAT1 2q32.2 91 IFN-g/IL-12 axis (Th1 diff.) Y

EGFR, FGFR3/4, JAK1/2, Lck, KIT, TYK2

STAT2 12q13.3 113 Y

JAK1 S

PKCd, CamKIIg,

Ribosomal protein S6 kinase alpha 5

STAT3 17q21.31 Th17

Y

FGFR3/4, Hck, JAK1/2, cSrc, EphA3

S

ERK1/2, PKCd, MAPK8, Ribosomal protein S6

kinase alpha 5

STAT4 2q32.2-q32.3 Th1 S

MAPK14, MAP2K6

STAT5A 17q11.2 Y

JAK2, Btk

STAT5B 17q11.2 Y

cSrc

Y

EGFR

STAT6 12q13 IL-4 (Th2 diff.) JAK1/2/3

STAT II

STAT1 IFN-I/II Inflammation

STAT2 IFN-I

STAT3 IL-6 and IL-10 families, IL-21, IL-27

STAT4 IL-12,-23 Th1, Th17

STAT5A and B IL-3,-5, GM-CSF

STAT6 IL-4,-13 Th2, allergy

Regulation of JAK/STAT signaling

• Phosphatases

SHP-1/2, CD45 – JAK

SHP-2, PTP1B, TC-PTP, PTP-BL – STAT

• Nuclear export/import

NES (nuclear export sequence)

NLS (nuclear localization sequence)

• SOCS (suppressors of cytokine signaling) eg. PIAS (Protein Inhibitor of Activated STATs)

• Ser-phosphorylation, acetylation, o-glycosylation of TAD

JAK inhibitors

Treatment:

• Polycythemia vera, thrombocytemia,

• Myeloid metaplasia, myelofibrosis

• Psoriasis

• RA

Examples:

• Lestaurtinib

• Tofacitinib

• Ruxolitinib

Chemokines

• 90-130 aa. polypeptides Functions:

• Chemotaxis for different leukocytes:

– Regulation of normal leukocyte traffic

– Recruitment of cells to inflammatory sites

• Enhancement of cell adhesion

• Activation of effector leukocytes

• Development of the inflammatory reaction

• Development of normal lymphoid tissues

coupled with G-proteins

Chemokine receptor Ca²⁺ channels

G protein

cAMP Adenylyl

cyclase

Adhesion

Chemotaxis

?

Differentiation, proliferation Ras

?

Actin polymerization PLCβ2

DAG IP₃

Ca²⁺

PKC

Cytoskeletal rearrangment

? GDP

β g a

GTP

a g

β

Chemokine signaling pathways

Chemokine receptor

Ca²⁺ channel

Gene expression and apoptosis Chemokines

Ca²⁺

Ca²⁺

RAS

DAG

JNK p38

Ras pathway β g

GRB2

NF-B c-Jun

c-Fos STAT5

PKC Ca²⁺

PYK2 Crk CAS

GTP a

Elk-1 MAPK pathway

PTK

Cell activation PLA2

Rho pathway

Rho

SRF Internalization

Degradation Recycling

GRK

β-Arrestin

PLCβ

PKCβ PLCg

PI3K

Akt/PKB pathway

Akt/

PKB PDK

NF-B

Elk-1 Elk-1

Plasma membrane

Cytoplasm

Nucleus

PIP₂

IP₃ GDP

β g a JAK2