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Protein Interaction Networks. Feb. 21, 2013. Aalt-Jan van Dijk Applied Bioinformatics, PRI, Wageningen UR & Mathematical and Statistical Methods, Biometris, Wageningen University aaltjan.vandijk@wur.nl. My research. Protein complex structures Protein-protein docking Correlated mutations
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Protein Interaction Networks Feb. 21, 2013 Aalt-Jan van Dijk Applied Bioinformatics, PRI, Wageningen UR & Mathematical and Statistical Methods, Biometris, Wageningen University aaltjan.vandijk@wur.nl
My research • Protein complex structures • Protein-protein docking • Correlated mutations • Interaction site prediction/analysis • Protein-protein interactions • Enzyme active sites • Protein-DNA interactions • Network modelling • Gene regulatory networks • Flowering related
Overview • Introduction: protein interaction networks • Sequences & networks: predicting interaction sites • Predicting protein interactions • Sequence and network evolution • Interaction network alignment
Protein Interaction Networks hemoglobin Obligatory
Protein Interaction Networks hemoglobin Mitochondrial Cu transporters Obligatory Transient
Experimental approaches (1) Yeast two-hybrid (Y2H)
Experimental approaches (2) Affinity Purification + mass spectrometry (AP-MS)
Interaction Databases • STRINGhttp://string.embl.de/
Interaction Databases • STRING http://string.embl.de/ • HPRD http://www.hprd.org/
Interaction Databases • STRING http://string.embl.de/ • HPRD http://www.hprd.org/ • MINT http://mint.bio.uniroma2.it/mint/
Interaction Databases • STRING http://string.embl.de/ • HPRD http://www.hprd.org/ • MINT http://mint.bio.uniroma2.it/mint/ • INTACT http://www.ebi.ac.uk/intact/
Interaction Databases • STRING http://string.embl.de/ • HPRD http://www.hprd.org/ • MINT http://mint.bio.uniroma2.it/mint/ • INTACT http://www.ebi.ac.uk/intact/ • BIOGRID http://thebiogrid.org/
Some numbers Organism Number of known interactions H. Sapiens 113,217 S. Cerevisiae75,529 D. Melanogaster 35,028 A. Thaliana13,842 M. Musculus 11,616 Biogrid (physical interactions)
Overview • Introduction: protein interaction networks • Sequences & networks: predicting interaction sites • Predicting protein interactions • Sequence and network evolution • Interaction network alignment
Binding site prediction Applications:
Binding site prediction Applications: • Understanding network evolution • Understanding changes in protein function • Predict protein interactions • Manipulate protein interactions
Binding site prediction Applications: • Understanding network evolution • Understanding changes in protein function • Predict protein interactions • Manipulate protein interactions Input data: • Interaction network • Sequences (possibly structures)
Sequences and networks • Goal: predict interaction sites and/or motifs
Sequences and networks • Goal: predict interaction sites and/or motifs • Data: interaction networks, sequences
Sequences and networks • Goal: predict interaction sites and/or motifs • Data: interaction networks, sequences • Validation: structure data, “motif databases”
Motif search in groups of proteins • Group proteins which have same interaction partner • Use motif search, e.g. find PWMs Neduva Plos Biol 2005
Correlated Motifs • Motif model • Search • Scoring
Correlated Motif Mining Find motifs in one set of proteins which interact with (almost) all proteins with another motif
Correlated Motif Mining • Find motifs in one set of proteins which interact with • (almost) all proteins with another motif • Motif-models: • PWM – so far not applied • (l,d) with l=length, d=number of wildcards • Score: overrepresentation, e.g. χ2
Correlated Motif Mining • Find motifs in one set of proteins which interact with • (almost) all proteins with another motif • Search: • Interaction driven • Motif driven
Interaction driven approaches Mine for (quasi-)bicliques most-versus-most interaction Then derive motif pair from sequences
Motif driven approaches Starting from candidate motif pairs, evaluate their support in the network (and improve them)
D-MOTIF Tan BMC Bioinformatics 2006
IMSS: application of D-MOTIF protein X protein Y Test error Number of selected motif pairs Van Dijk et al., Bioinformatics 2008 Van Dijk et al., Plos Comp Biol 2010
Experimental validation protein X protein Y Test error Number of selected motif pairs Van Dijk et al., Bioinformatics 2008 Van Dijk et al., Plos Comp Biol 2010
Experimental validation protein X protein Y Test error Number of selected motif pairs Van Dijk et al., Bioinformatics 2008 Van Dijk et al., Plos Comp Biol 2010
Experimental validation protein X protein Y Test error Number of selected motif pairs Van Dijk et al., Bioinformatics 2008 Van Dijk et al., Plos Comp Biol 2010
SLIDER Boyen et al. Trans Comp Biol Bioinf 2011
SLIDER • Faster approach, enabling genome wide search • Scoring: Chi2 • Search: steepest ascent
Validation • Performance assessment on simulated data • Performance assessment using using protein structures
Extensions of SLIDER • Extension I: better coverage of network Boyen et al. Trans Comp Biol Bioinf 2013