Vorlesung: Molekulare Mechanismen der Signaltransduktion

Vorlesung: Molekulare Mechanismen der Signaltransduktion

Literatur Lehrbuch der Molekularen Zellbiologie von Bruce Alberts et al.

Molekulare Zellbiologie 799 Seiten - Wiley-VCH Erscheinungsdatum: 13. September 2001 Auflage: 2. Aufl. ISBN: 3527304932 Preis: 59,00€

von Harvey Lodish ,Arnold Berk , S. L. Zipursky ,James Darnell

Molekularbiologie der Zelle, m. CD-ROM

von Bruce Alberts ,Alexander Johnson ,Julian Lewi

1300 Seiten - Spektrum Verlag Erscheinungsdatum: Oktober 2001 ISBN: 3827410770 Preis: EUR 79,95

1863 Seiten - Wiley-Vch Erscheinungsdatum: Dezember 2003 ISBN: 3527304924 Preis: 109,00€

Literatur Biochemie der Regulation und Signaltransduktion von Gerhard Krauss

522 Seiten - Wiley-VCH Verlag Erscheinungsdatum: Juli 1997 ISBN: 3527293930 Preis: 79,00€ (deutsch)

Immunobiology, w. CD-ROM von Charles A. Janeway , Paul Travers ,Mark Walport

528 Seiten - Wiley-VCH Erscheinungsdatum: 17. Juli 2001 Auflage: 2. Aufl. ISBN: 3527303782 Preis: 89,00€ (englisch)

Signal Transduction von Bastien Gomperts

Sprache: Englisch Broschiert - 848 Seiten - Churchill Livingstone Erscheinungsdatum: Juli 2004 ISBN: 0443073104

EUR 62,00

424 Seiten - Academic Press Erscheinungsdatum: 1. März 2002 ISBN: 0122896319 Preis: 74.o5€

General Principles in Signal Transduction Signals

Receptors

Mediator(s)

Effector(s)

Response

-Kinases -Phospholipases -GTPases -Adaptors -Transcription Factors -Structural Proteins -Enzymes -Proliferation -Differentiation -Apoptosis -Cell activation

General Principles in Signal Transduction

General Principles in Signal Transduction

General Principles in Signal Transduction

General Principles in Signal Transduction

General Principles in Signal Transduction

General Principles in Signal Transduction

General Principles in Signal Transduction

General Principles in Signal Transduction Signals

Receptors

Hydrophobic Signals

Hydrophilic Signals

Mediator(s) Intracellular Receptors

Response

General Principles in Signal Transduction

Steroid Receptor Family • Cytoplasmic transcription factors • Bind lipophilic ligands – Estrogen, progesterone, testosterone – Vitamin D Steroid sex hormones – Glucocorticoids and mineralocorticoids – Thyroid hormone (nuclear receptor)

Steroid Receptor Signaling

Steroid Receptor Signaling

Steroid Receptor Structure

General Principles in Signal Transduction

General Principles in Signal Transduction A

B

D

C

Different classes of cell surface receptors

O. Modlich 24.5.

J. Bode 3./10.5.

nächste Woche

W. Schulz 17.5.

Two main apoptosis signaling pathways F. Essmann (14.6.)

Death ligand

Death receptor) FADD

cytokines

Bad

TCR

Bim

p53

Puma Noxa

Pro-Caspase-8 Bcl-2 Bcl-xLL

Bid Caspase-8 (active)

Bax Bak mitochondrium Caspase-9

Omi/HtrA2

AIF

Smac/Diablo

Cyt c

Apaf-1

IAP

cytoplasm

Caspase-3 (executioner caspases)

DFF/CAD

Death Substrates

Caspase-independent Death DNA Fragmentation

nucleus

General Principles in Signal Transduction Signals Hydrophilic Signals Receptors

Mediator(s)

Response

General Principles in Signal Transduction

-Kinases -Phospholipases -Second messengers -GTPases -Adaptors

Biochemical Reactions in Signal Transduction Kinases

-protein kinases phosphorylate their substrates -phosphorylation changes the activity, subcellular location, or aggregation of the proteins

Biochemical Reactions in Signal Transduction Kinases Nucleophiler Angriff

Energiegefälle: Kein Rückreaktion !

Biochemical Reactions in Signal Transduction Kinases Primary structure of a kinase Kinase domain ( approx. 30 kDa) Subdomains

I

II

III

IV

V

AXK

VI

VII

VIII

IX

X

XI

Activation loop (T-loop)

Tyr Kinases: Src, EGF-R, PDGF-R, JAK Ser/Thr Kinases: PKC, Raf, MAPK, Akt Dual-specificity kinases: MEK, MKK Lipid Kinase: PI3K

General Principles in Signal Transduction

-Kinases -Phospholipases -Second messengers -GTPases -Adaptors

Biochemical Reactions in Signal Transduction Phospholipases

-phospholipase C (PLC) catabolizes phospholipids (PIP2) generating IP3 -IP3 binds a receptor and increases cytosolic calcium -increased cytosolic calcium activates other signaling mechanisms

General Principles in Signal Transduction

-Kinases -Phospholipases -Second messengers -GTPases -Adaptors

Second Messengers • Cyclic nucleotides – Cyclic AMP and cyclic GMP

• Lipid metabolites – Diacylglycerol – Inositol triphosphate

• Calcium

General Principles in Signal Transduction

-Kinases -Phospholipases -Second messengers -GTPases -Adaptors

General Principles in Signal Transduction GTP-binding proteins in signal transduction

a) G-Proteins (heterotrimeric GTPases)

b) monomeric GTPases = small GTPases = ras-like GTPases

G protein coupled receptors

G proteinbild andreas Simm

G protein coupled receptors Activation of Adenylate Cyclase by Gs

G protein coupled receptors - cAMP generation Function of Adenylate Cyclase

G protein coupled receptors - PKA activation

Molecular Biology of the Cell, 2002

Activation of cAMP-dependent protein kinase (PKA) cAMP binds to the PKA regulatory subunits → conformational changes, which causes their dissociation from the catalytic subunits → kinase activation. Release of the catalytic subunits requires the binding of more than two cyclic AMP molecules greatly sharpening the response of the kinase to changes in [cAMP]. PKA is a Ser/Thr kinase with discrete substrate specificity, thus facilitating a cascade of highly regulated protein phosphorylations.

General Principles in Signal Transduction GTP-binding proteins in signal transduction

a) G-Proteins (heterotrimeric GTPases)

b) monomeric GTPases = small GTPases = ras-like GTPases

Biochemical Reactions in Signal Transduction GTPases

GEFs

GAPs Signal -G proteins are turned “on” and “off” by GTP and GDP, respectively - active G proteins transmit the signal to other “downstream” proteins

Biochemical Reactions in Signal Transduction GTPases GTPases: Ras, Rac1, Rho, Cdc42 GEFs: Sos, Ras-GRP, Vav1

Vav1

General Principles in Signal Transduction

-Kinases -Phospholipases -Second messengers -GTPases -Adaptors

Biochemical Reactions in Signal Transduction Adaptor proteins

Example: SH2 domains -recognize phosphoryated tyrosines -Recruit signaling proteins to receptor

-adaptors have no enzymatic activity of their own -function is to recruit signaling enzymes to the receptor-ligand complex -this concentrates signaling proteins and increases efficiency

Biochemical Reactions in Signal Transduction SH2 Adaptor Proteins • • •

Example: SH2 domains -recognize phosphoryated tyrosines -Recruit signaling proteins to receptor

Many proteins have a domain called SH2 Portion that recognizes phosphotyrosine Interacts with phosphotyrosine (like a ligand and receptor)

xxxxxYxxxx

P xxxxxYxxxx

Biochemical Reactions in Signal Transduction Adaptor proteins Protein-protein interaction domains SH2

14-3-3

SH3

P -Y-X-X-hyPTB

-P-X-X-P-X-

R-S-X-S-X-P

WW

PH

P -hy-X-N-P-X-Y-

P

-P-P-X-Y-

PIP3

Biochemical Reactions in Signal Transduction Adaptor proteins Cytoplasmic adaptor proteins MW (kD)

Interaction partners

Expression

Grb2

28

Sos,LAT,c-Cbl,Shc,SLP-76, Vav,SHP-2,WASP,HPK1

ubiquitous

Grap

28

Sos,LAT,Shc,SAM68

B-Cells, T-Cells

Name

Structure

PxxP

Gads Nck-1

47 PxxP

Shb PxxP

Shc

PxxP

40

PxxP

SH2-Binding Site SH3-Binding Site

55,66 46,52,66

SH3-Domain

T-Cells, NK Cells Mast cells. Macrophages, Thrombocytes Sos,SLP-76,WASP,PAK,Cbl ubiquitous LAT,Shc,SLP-76,HPK1

Grb2,LAT,PI3K,Eps8, PLCγ1,CD3ζ,Src Grb2,SHIP,ZAP-70,CD3ζ, Igα/β,RasGAP

PTB-Domain

ubiquitous ubiquitous

SH2-Domain

Biochemical Reactions in Signal Transduction Adaptor proteins Transmembrane adaptor proteins Name

Structure

MW (kD)

Interaction partners

Expression

36-38

Grb2,Gads,SLP-76, PLCγ1/2,c-Cbl,PI3K

T-Cells, NK Cells, Mast cells, Platelets

75-85

Csk,Fyn

Ubiquitous

SIT

30-40

SHP2

B-Cells, T-Cells

TRIM

29-30

PI3K

T-Cells, NK Cells

LAT PAG/Cbp

PxxP

PxxP

TM

PxxP

SH2-Binding Site SH3-Binding Site

A. Leo and B.Schraven, Current Opinion in Immunology, 2001

Next week: Signaling from receptor tyrosine kinases

Stimulates Mitogen Activated Protein kinases (MAPK)