Lecture of Cell Signaling-I

Dec. 7, 2004

Contact information:Tzu-Ching MengLab 614, IBC, Academia SinicaTel: 27855696 ext 6140Email: tcmeng@gate.sinica.edu.tw

Phosphorylation is reversible

Y

Protein

YPP

P

Y

Protein

Y

PY

P

Y

P

PTPs

PTKs

Protein modules inthe control of intracellularsignaling pathways

Docking proteins functionas platforms for the recruitmentof signaling molecules

Models for activation ofSignaling proteins

A). By membrane translocation

B). By conformational change

C). By tyrosine phosphorylation

Signaling pathways activated by receptortyrosine kinases

Mechanisms for attenuationof receptor tyrosine kinases

Classification of human receptor tyrosine kinases (RPTKs)

Classification of human cytoplasmic protine tyrosine kinases

Activation of receptor tyrosine kinases

Juxtamembrane region

Substrate precluding loop

Substrate accessible loop

N-terminal kinase lobe

C-terminal tail

Activation of c-Src

Two modes of intrinsic inhibitionby interactions between:(1) SH2 domain and phosphorylated Y527;(2) SH3 domain and Polyproline region.

Activation of PKB/Akt

PH domain precludesKinase access by PDK-1

*

*

*

*

*

In most cases of CML, the leukemic cells share a chromosome abnormality not found in any nonleukemic white blood cells, nor in any other cells of the patient's body. This abnormality is a reciprocal translocation between one chromosome 9 and one chromosome 22. This translocation is designated t(9;22). It results in one chromosome 9 longer than normal and one chromosome 22 shorter than normal. The latter is called the Philadelphia chromosome and designated Ph1.

Expression of afusion PTKp210 Brc-Abl

RetinaldehydeBinding protein-like

PTP1BTCPTP

SHP1 SHP2

MEG2

PESTLyPTP

PTPH1 MEG1PTPD1PTPD2

PTPBAS

CD45

PTPPTPPTPPTP

LARPTPPTP

PTPPTP

PTPPTP

PTPDEP1SAP1

GLEPP1

PEST

SH2

SH2

FERM

FNFNFNFNFNFNFNFNFNFNFNFNFNFNFNFN

FNFNFNFN

FNFN

FN

MAM

Receptor-type PTPsNon-transmembrane PTPs

FNFNFNFNFNFNFNFNFN

‘Classical’ pTyr Specific PTPs (HCSAGxGRxG)

VHRVH1

MKP-1MKP-2MKP-3MKP-4MKP-5

Dual Specificity Phosphatases (HCxxGxxR)

VHR-like

PTEN

Cdc25

The Protein Tyrosine Phosphatase Superfamily (HCx5R)

FYVE-DSP

PTEN(MMAC1)

Cdc25ACdc25BCdc25C

FYVE

KAP(Cdi1)

C2

FN

MAM

Merpin/A5/domain

FERMPTP domain

Src Homology domain 2

PDZ domain

PEST-like

FERM domain

SH2

PEST

Fibronectin IIILike repeat

Immuno-globulin-like

Cadherin-like

Carbonic anhydrase-like

Heavily glycosylated

FYVE

DSP domain

FYVE-domain

C2 Lipid binding domain

Tonks NK & Neel BG, Curr Opin Cell Biol. 2001, 13(2):182-95

Classification of Protein Tyrosine Phosphatases

Non-transmembrane PTPs Receptor-like PTPs

Andersen et al., Mol Cell Biol, 21, 7117, 2001

C-terminal- ER targeting- Proteolytic cleavageProline rich segment- SH3 binding sitesAlternative splicing- Nucleus vs Cytoplasmic

Functional Diversity Through Targeting and Regulatory Domains

SH2 domains- Plasma membrane signaling complexes- Auto-inhibition

Cellular retinaldehyde binding protein-like- Golgi targeting- Secretory vesicles

- Putative lipid-binding domain

FERM domain- Subcellular targeting (e.g. cytoskeletal proteins) PDZ domain(s)- Protein-Protein interactions

PEST domain- Protein-Protein InteractionsBRO1 domain- Functionally uncharacterised; (Found in a number of signal transduction proteins) - Vesicle associatedHis-domain- Functionally uncharacterised

Sequence comparison of human PTP domains

PxxVHCSAGxGRTG

(M9)

WPDxGxP(M8)

IVMxT (M6) KCxxYWP (M7)

TxxDFWxMxW

(M5)

DxxRVxL(M2)DYINA

(M3)NxxKNRY

(M1)

IAxQGP(M4)

QTxxQYxF(M10)

Location of conserved motifs in 3D

http://ptp.cshl.edu

Conserved fold of PTP domains

N-terminal

Central -helixAndersen et al Mol. Cell. Biol. 2001

Protein Tyrosine Phosphatase 1B

WPD loop

PTP Catalytic Mechanism

RetinaldehydeBinding protein-like

PTP1BTCPTP

SHP1 SHP2

MEG2

PESTLyPTP

PTPH1 MEG1PTPD1PTPD2

PTPBAS

CD45

PTPPTPPTPPTP

LARPTPPTP

PTPPTP

PTPPTP

PTPDEP1SAP1

GLEPP1

PEST

SH2

SH2

FERM

FNFNFNFNFNFNFNFNFNFNFNFNFNFNFNFN

FNFNFNFN

FNFN

FN

MAM

Receptor-type PTPsNon-transmembrane PTPs

FNFNFNFNFNFNFNFNFN

‘Classical’ pTyr Specific PTPs (HCSAGxGRxG)

VHRVH1

MKP-1MKP-2MKP-3MKP-4MKP-5

Dual Specificity Phosphatases (HCxxGxxR)

VHR-like

PTEN

Cdc25

The Protein Tyrosine Phosphatase Superfamily (HCx5R)

FYVE-DSP

PTEN(MMAC1)

Cdc25ACdc25BCdc25C

FYVE

KAP(Cdi1)

C2

FN

MAM

Merpin/A5/domain

FERMPTP domain

Src Homology domain 2

PDZ domain

PEST-like

FERM domain

SH2

PEST

Fibronectin IIILike repeat

Immuno-globulin-like

Cadherin-like

Carbonic anhydrase-like

Heavily glycosylated

FYVE

DSP domain

FYVE-domain

C2 Lipid binding domain

Tonks NK & Neel BG, Curr Opin Cell Biol. 2001, 13(2):182-95

Sequence alignment of amino acid residues at phosphatase motif among human DSPs

Amino acid sequence homologies of human DSPs

Catalytic mechanism of DSPs

Mammalian MAP kinase cascades

MAPK and SAPK pathway in mammalian cells

T-x-Y at the activation loop

Function of MAP Kinase Phosphatases (MKPs)

Localisation Inducible Substrate specificity

MKP1 Nuclear Growth factors,

Stress

ERKs=JNKs=p38

MKP2 Nuclear NGFEGF

ERKs>JNKs>>p38

MKP3 Cytosolic No ERKs>>>JNKs=p38

MKP4 Cytosolic ERKs>>JNKs=p38

MKP5 ERK6

PAC-1 Nuclear Mitogen ERKs>p38>>JNKs

hVH-5 Cytosolic JNKs>p38>>>>ERKs

Pyst2 Cytosolic No

VHR No ERK1,ERK2

B23 Nuclear StressMitogen

Mechanism of action of MAP kinase phosphatases (MKPs)

Inactivation of MAP kinases (ERK) by threonine or tyrosine dephosphorylation

The mammalian MAP kinase phosphatases (MPKs)

PTPs and Cancer

Refinement of PTP chromosomal positionsallows for genetic disease linkage studies

19 PTP chromosomal regions are frequently deleted in human cancers

3 PTP chromosomal regions are frequently duplicated in human cancers

 PTEN Tumor Suppressor Mutated in various human cancers. Cowden disease

DEP1 Tumor suppressor Colon cancer susceptibility locus Scc1 (QTL in mice)

PTP Tumor Suppressor Primary CNS lymphomas

SHP2 Noonan Syndrome Developmental disorder affecting 1:2500 newbornStomach Ulcers Target of Helicobacter pylori

 Cdc25 Cell Cycle Control Target of Myc and overexpressed in primary breast cancer

PRL-3 Metastasis Upregulated in metastases of colon cancer

FAP-1 Apoptosis Upregulated in cancers, inhibits CD95-mediated apoptosis 

PTPs and Cancer

PTPs as Drug Targets

PTPs

Diabetes& Obesity

Cancer

Autoimmunity& Allergy

Immunosupression

Infectiousdiseases

Epilepsy

P

P

PTK

(Inactive)

PTK

(Active)

S

(Active)

S

(Inactive)

Autophosphorylation

PTP

PTP

P

P

Interactions Between PTKs and PTP– (1)PTPs function as NEGATIVE Regulators

of Signal Transduction

S

(Inactive)

S

(Active)

PTK

PTP

P

P

Interactions Between PTKs and PTPs—(2)PTPs function as POSITIVE Regulators of

Signal Transduction

Important references

1. Hunter, T. (2000) Signaling-2000 and beyond. Cell, 100: 113-1272. J. Schlessinger (2000) Cell signaling by receptor tyrosine kinases. Cell, 103: 211-2253. Myers, M. et al. (2001) TYK2 and JAK2 are substrates of protein tyrosine phosphatase 1B. J. Biol. Chem., 276: 47771-477744. Andersen, J. N. et al. (2001) Structural and evolutional relationships among protein tyrosine phosphatase domains. Mol. Cell. Biol., 21: 7117-71365. Tonks, N. K. (2003) PTP1B: From the sidelines to the front lines. FEBS Letters, 546: 140-148

Additional references

1. Blume-Jensen, P. Hunter, T. (2000) Oncogenic kinase signaling. Cell, 100: 113-127.

2. Palka, H., Park, M. and Tonks, N.K. (2003) Hepatocyte growth factorreceptor kinase Met is a substrate of the receptor protein tyrosine phosphatase DEP-1. J. Biol. Chem., 278: 5728-5735.

3. Salmeen, A. et al. (2000) Molecular basis for the dephosphorylationof the activation segment of the insulin receptor by protein tyrosinephosphatase 1B. Mol. Cell, 6: 1404-1412.

4. Meng, T.C. et al (2004) Regulation of insulin signaling through reversible oxidation of the protein-tyrosine phosphatases TC45 and PTP1B. J. Biol. Chem., 279: 37716-37725.