generic signal transduction pathwaysweb.mit.edu/7.61/restricted/pdfs/lect4_kinase.pdfreceptors...
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Generic Signal Transduction Pathways
ProliferationSurvival
Differentiation
Apoptosis
Cytoskeleton
LIGANDS
RECEPTORS
ADAPTORS
EFFECTORS
OUTPUTS
Downward, J. 2001
Nature N&V
Ln
Rn
Gn
CHANNELS
AC cAMP cAKinase
PDE cGMP cGKinase
CHANNELS
PLA
PLC
Arachidonic
acid
Prostaglandins
Eicosanoids
PIP2
IP3
Ca++ CaMKinase
DAG
Kinase C
PI derivatives
Kinase B/Akt
PI3K
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RECEPTORS TRANSDUCERS EFFECTORS
(proximal)
“SECOND
MESSENGERS”
SERPENTINE
(7TM)
HETEROTRIMERIC
G PROTEINS
ADENYLATE
CYCLASE
PHOSPHODI-
ESTERASE
PHOSPHO-
LIPASE C!
PI3 KINASE
CHANNELS
cAMP
cGMP
DERIVATIVES
DERIVATIVES Ca++
PHOSPHATIDYL
INOSITOL
PHOSPHATES
IONS
+DIACYLGLYCEROL
IP3
GsGi
Gt
Go
Gq !"
Gt!"
various incl.!"
ADENYLATE
CYCLASE
PHOSPHO-
DIESTERASE
Gs Gi
Gt
cAMP
cGMP
Note:
There are also
Guanylate Kinase
Receptors
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SECOND MESSENGER EFFECTORS
cAMP
cGMP
Ca++
DAG PKC Protein Kinases C
PKA Protein Kinase A
Calmodulin (CaM) CaM Kinases
Other Ca++-activated kinases eg MLCK
Other effectors - cAMP phosphodiesterase
- Calcineurin, a Ca++-activated phosphatase
- cytoskeleton
Some but not all Ca++- dependent
Activated by phorbol esters
Channels/Pumps
cGMP-dependent kinases
PM-NUCLEUS
See also
Brivanlou & Darnell
Science 295:813-818
(2002)
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RTK-P
RTK
PhosphataseLigand
Signaling
GGTP
GGDP
Ligand
Signaling
GEFs GAPs
RGSs
GDIs
Receptor Protein Tyrosine Kinases
Ig
Fn3
HGF/SF
Neurotrophins
Ephrins Gas6
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Dimerization Trans-phosphorylation
RecruitmentActivation
HGH/HGHR
1 monomeric ligand
2 receptors
R-R interactions
Asymmetric
Also Epo/EpoR
Kosiakoff, De Vos
and Wells
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VEGF/VEGFR
1 dimeric ligand
2 receptors
R-R interactions
Symmetric
also PDGF, NGF, TGF/BMP
Wiesman et al, Cell 91:695-704 1997
EGF/EGFR
2 monomeric ligands
2 receptors
R-R interactions
Symmetric
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FGF/FGFR
2 monomeric ligands
2 receptors
2 heparin chains
R-R interactions
Overall symmetric
but L-R binding is
two-site, asymmetric
Schlessinger et al, Mol. Cell 6: 743-750 2000
Mohammadi et al, Curr Opin Struc Biol. 15: 506-516, 2005
Receptor Autoinhibition
• EGFR extracellular domain undergoes conf. change on EGF binding
• BUT EGFR extracellular domain does not dimerize on EGF binding
• Intact EGFR DOES dimerize on EGF binding
• MODEL - ECD conformation blocks dimerization (autoinhibition)
and that is relieved by ligand
• sEGFR is mostly monomeric and low affinity (400-550 nM)
• there is a small population (~5%) with high affinity (2-20 nM)
• deletion of domain IV converts it to high affinity (13-21 nM)
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Autoinhibition of EGFRs
IV
Cho and Leahy
Science (2002)
EGFEGF
EGF
Autoinhibition of FGFRs
FGFR
FGF
FGF
D3
D2
D3
D2
D1
D1
D1
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PDGF-Receptor
Recruitment of signal transducers
to tyrosine phosphates
Protein Modules Recruiting Signaling Proteins
to Receptors and to the Membrane
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Insulin Receptor Substrate (IRS)etc
An alternative way
to recruit
signal transducers-Y-P
P-Y-
-Y-PY-PP-Y
IRS
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Different Mechanisms for Activating
Signaling Proteins
Recruitment
plus Activation
& Phosphorylation
Recruitment with
Conformational
Change -> Activation
Recruitment plus
Phosphorylation
-> Activation
Receptor -> MAPKinase pathway
MAPK
MAPKK
MAPKKK
MAPKK and MAPK
activations involve
BOTH Y and S/T
phosphorylations
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Evolutionary Conservation of
MAPKinase Pathways
MAPK
MAPKK
MAPKKK
Effectors
MAP Kinase Pathways/Cascades
Why cascades? How does the cell keep modules separate?
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switches
Ferrell, TIBS 21: 460-466 (1996)
Cascade as a switch mechanism
Mos -> ->Erk
Is there amplification?
Model Results
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 50
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1Fig. 1: Replica of Fig. 2A - Predicted responses on a linear plot
Input stimulus (E1tot
in multiples of the EC50)
Predicted Steady-State Kinase Activity
MAPKKK
MAPKK
MAPK
MAPKKK
MAPK
10-6
10-5
10-4
10-3
10-2
10-1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1Fig. 2: Replica of Fig. 2B - Predicted responses on a semi-logarithmic plot
Input stimulus (E1tot
)
Predicted Steady-State Kinase Activity
MAPKKK
MAPKK
MAPK
MAPKKK
MAPK
nH = 1.0
nH = 4.9
Huang C.F. & Ferrell J.E. (1996)
PNAS 93, 10078-83
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Experimental Validation
Huang C.F. & Ferrell J.E. (1996)
PNAS 93, 10078-83
Scaffolds for MAPK modules
Ste11p Ste7p Fus3p
MAPKKK MAPKK MAPK
Ste5p
MLK MKK7 JNK
JIP1
MLK MKK3 p38
JIP2
kinesin
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More Scaffolds for MAPK modules
MEK1 ERK1
MAPKKK MAPKK MAPK
MP1late endosomesp14
Focalcontacts
SH2-SH3-SH3
CrkII
p130Cas
paxillinC3G
SOS
DOCK180
(via PPxLPxK)
GEFs
also in JNKMutation blocks
JNK activation by EGF/rac
but not by UV
!-arrestins
GPCR/arr/raf/erk
complexes on
endocytosis
Morrison & Davis
ARCDB 19:91-118
(2003)
RTK-P
RTK
PhosphataseLigand
Signaling
Kinase*
Kinase
RLigand
Signaling
Phosphatase
Receptor-intrinsic
kinases
Receptor-associated
kinases
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ITAM - YxxLx6-8YxxL
Src family kinase ITAM-binding
(2xSH2) kinase
MHC/peptide
CD3 complexTCR
T Cell Receptor Signaling
P P
Cytokine Receptors
Shared signaling subunits - different ligand-binding subunits
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JAK/Stat IRS etc
Cytokine Receptors
Signaling Pathways
TGF! Receptor Family - S/T Kinases
II IIII
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TGF! Receptor Family - SMAD Signaling
TGF! Receptor Family -
Regulators and Feedback Loops
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Protein Tyrosine Phosphatases
Protein Tyrosine Phosphatases
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Structure of PTPase domain
D1 from receptor-like
Protein phosphatase-#
Bilwes et al.
Nature 382:555-559
(1996)
wedge
active
site
T Cell Receptor Signaling
Src family kinase ITAM-binding
(2xSH2) kinase
MHC/peptide
CD3 complexTCR
CD45
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Negative Feedback Regulation