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An Introduction to Modeling Biochemical Signal Transduction Jim Faeder Department of Computational and Systems Biology University of Pittsburgh School of Medicine 2014 CMACS Winter Workshop Lehman College
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Cell as Information Processor http://en.wikipedia.org/wiki/Cell_signaling
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The cellular brain http://www.biochemweb.org/fenteany/research/cell_migration/neutrophil.html Original film from David Rogers (Vanderbuilt University)
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Organization of Signaling Networks Yarden & Sliwkowski, Nature Rev. Mol. Cell Biol. 02: 127-137 (2001).
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Ras in network context The Biology of Cancer (© Garland Science 2007)
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Figure 5.15 The Biology of Cancer (© Garland Science 2007) Initiating Events: Receptor Aggregation
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Figure 6.12 The Biology of Cancer (© Garland Science 2007) Initiating Events: Complex Formation “Effector” Activation
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Ras at Multiple Scales The Biology of Cancer (© Garland Science 2007) >20% human tumors carry Ras point mutations. >90% in pancreatic cancer. >20% human tumors carry Ras point mutations. >90% in pancreatic cancer. Transformed
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Video of Ras Activation Ras structure and function
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Ras Structure to Model
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Ras pi3kral gn sosraf ~GDP ~GTP Sos Ras GAP Ras GAP Raf PI3K Ral
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Ras Biochemistry to Rules Ras bound to GDP binds to Sos nuc Ras eff + Sos cat RasGEF RasSos Sos binding catalyzes GDP/GTP exchange RasSos RasSos RasGTP binds Raf Ras + Raf Ras Raf RBD
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BioNetGen Language Formalizes Object- Oriented Description of Biochemistry Ras Sos Ras Raf Molecules SpeciesPatterns Raf Sos(RasGEF) Ras(cat,nuc~GDP~GTP,eff)Raf(RBD) RasSos Sos(RasGEF!1).Ras(cat!1,nuc~GTP) Ras(nuc~GTP,eff!1).Raf(RBD!1)
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BioNetGen Language Formalizes Object- Oriented Description of Biochemistry Ras Sos Ras Raf Molecules SpeciesPatterns Raf Sos(RasGEF) Ras(cat,nuc~GDP~GTP,eff)Raf(RBD) RasSos By leaving out a component this graph becomes a selector for multiple graphs. Sos(RasGEF!1).Ras(cat!1,nuc~GTP) Ras(nuc~GTP,eff!1).Raf(RBD!1)
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BioNetGen Language Formalizes Object- Oriented Description of Biochemistry Rules Sos binding catalyzes GDP/GTP exchange RasSos RasSos RasGTP binds Raf Ras + Raf Ras Raf Sos(RasGEF!1).Ras(cat!1,nuc~GDP,eff)-> \ Sos(RasGEF!1).Ras(cat!1,nuc~GTP,eff) k2 Ras(nuc~GTP,eff)+Raf(RBD) Ras(nuc~GTP,eff!1).Raf(RBD!1) kp3,km3
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“Object-Oriented” Representation of Signaling Molecules IgE(a,a) FceRI(a,b~U~P,g2~U~P) Lyn(U,SH2) Syk(tSH2,lY~U~P,aY~U~P) B IO N ET G EN Language Faeder et al., Meth. Mol. Biol. (2009)http://bionetgen.org
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Concise and Precise Description of Biochemical Knowledge Transphosphorylation component state change Lyn(U!1).FceRI(b!1).FceRI(b~U)-> \ Lyn(U!1).FceRI(b!1).FceRI(b~P) Rules can query the local environment. Transformation only takes place when conditions are favorable.
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Composition of a Rule-Based Model MoleculesReaction Rules begin reaction_rules # Ligand-receptor binding 1 Rec(a) + Lig(l,l) Rec(a!1).Lig(l!1,l) kp1, km1 Rec(a) + Lig(l,l) Rec(a!1).Lig(l!1,l) kp1, km1 # Receptor-aggregation 2 Rec(a) + Lig(l,l!1) Rec(a!2).Lig(l!2,l!1) kp2,km2 # Constitutive Lyn-receptor binding 3 Rec(b~Y) + Lyn(U,SH2) Rec(b~Y!1).Lyn(U!1,SH2) kpL, kmL … begin molecules Lig(l,l) Lyn(U,SH2) Syk(tSH2,l~U~P,a~U~P) Rec(a,b~U~P,g~U~P) end molecules BioNetGen language
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AIM: Model the biochemical machinery by which cells process information (and respond to it). RepresentationSimulation Modeling cell signaling How do we simulate dynamics of signaling networks?
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Standard Chemical Kinetics Species Reactions
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Reaction Network Model of Signaling Kholodenko et al., J. Biol. Chem. 274, 30169 (1999) EGF EGFR GRB2 SOS EGF EGFR GRB2 SOS SHC
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Reaction Network Model of Signaling Kholodenko et al., J. Biol. Chem. 274, 30169 (1999) 22 species 25 reactions
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General formulation of chemical kinetics (continuum limit) x is vector of species concentrations S is the “stoichiometry matrix”, S ij = number of molecules of species i consumed by reaction j. v is the “reaction flux vector”, v j is the rate of reaction j. For an elementary reaction,
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RepresentationSimulation Modeling cell signaling Reaction Network How does set of Molecules and Rules get transformed into a Reaction Network of Species and Reactions?
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BioNetGen A b Y1 B A(b,Y1) B(a) Molecules are structured objects (hierarchical graphs) a BNGL: Faeder et al., In Methods in Molecular Biology: Systems Biology, Ed. I.V. Maly (2009)
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BioNetGen A b Y1 B A(b,Y1) B(a) Molecules are structured objects (hierarchical graphs) Rules define interactions (graph rewriting rules) A B + k +1 k -1 A B A(b) + B(a) A(b!1).B(a!1) kp1,km1 a bond between two components a Faeder et al., In Methods in Molecular Biology: Systems Biology, Ed. I.V. Maly (2009) BNGL:
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Rules generate events A B + k +1 A B Rule1 A b Y1 B a + Reaction1 12
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Rules generate events A B + k +1 A B Rule1 A b Y1 B a + Reaction1 12
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Rules generate events A B + k +1 A B Rule1 A b Y1 B a A b B a k +1 + Reaction1 123
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Rules may specify contextual requirements A b Y1 Rule2 p1p1 A b Y1 P context not changed by rule must be bound A b Y1 B a 3 Reaction2 A(b!+,Y1~U) -> A(b!+,Y1~P) p1 BNGL: context
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Rules may specify contextual requirements A b Y1 Rule2 p1p1 A b Y1 P context not changed by rule must be bound A b Y1 B a 3 Reaction2 A(b!+,Y1~U) -> A(b!+,Y1~P) p1 BNGL: context
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Rules may specify contextual requirements A b Y1 Rule2 p1p1 A b Y1 P context not changed by rule must be bound A b Y1 B a 3 Reaction2 p1p1 A b Y1 B a 4 P A(b!+,Y1~U) -> A(b!+,Y1~P) p1 BNGL: context
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Rules may generate multiple events Second reaction generated by Rule 1 A B + k +1 A B Rule1 A b Y1 B a A b B a k +1 + Reaction3 425 P absence of context P
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More complex rules Lyn Fc RI 22 P SH2 p* L P P Lyn Fc RI Transphosphorylation of 2 by SH2-bound Lyn Generates 36 reactions (dimer model) with same rate constant Lyn Fc RI 22 P SH2 p* L Lyn Fc RI 22 P SH2 P example
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Automatic Network Generation Seed Species (4) Reaction Rules (19) New Reactions & Species FcεRI Model Network FcεRI (IgE) 2 Lyn Syk Network
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Automatic Network Generation Seed Species (4) Reaction Rules (19) FcεRI Model FcεRI (IgE) 2 Lyn Syk 354 Species 3680 Reactions 354 Species 3680 Reactions
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Automatic Network Generation Seed Species (4) Reaction Rules (19) FcεRI Model FcεRI (IgE) 2 Lyn Syk 354 Species 3680 Reactions 354 Species 3680 Reactions
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