Protein‐Protein Interac-on Networks
Predic-on, Visualiza-on and Analysis
Vijayaraj Nagarajan PhD
Computa4onal Molecular Biology Specialist
Bioinforma4cs and Computa4onal Biosciences Branch
Na4onal Ins4tute of Allergy and Infec4ous Diseases
Office of Cyber Infrastructure and Computa4onal Biology
Outline
• Introduc4on to Interac4on Networks
• Basic components of an interac4on network
• Types of interac4on networks
• Predic4ng Protein‐Protein Interac4on Networks
• Methods
» Logic and concept
• Available Interac4on data
• Integrated protein‐protein interac4on databases
• Searching for interac4on data
• Network Visualiza4on and Analysis tools
• Popular visualiza4on tools
• Network analysis
• Demonstra4on
• Predic4on of interac4on (PPI…?) network from microarray (ARACNE)
• Visualiza4on and analysis of the predicted network (Cytoscape)
• Nodes
– DNA/RNA/Protein/Metabolite
• Edges
Directed
– Dis4nc4on between source and target
» Ac4va4on (direct/indirect)
» Repression (direct/indirect)
Undirected
– No dis4nc4on between source and target
» Co‐expression (indirect)
» Binding (direct)
Interac-on Networks – Basic Components
Interac-on Networks ‐ Basic Features
• Degree
• Number of connec4ons that a node has
• Distance
• Number of connec4ons between two
nodes, in a shortest path
• Path
• A sequence of connec4ons
• Is there a path (reachability)
• Mean Shortest Path distance (closeness)
• In how many shortest paths
(betweenness)
• Size of a network (Number of nodes)
• Density of a network (Propor4on of the connec4ons)
• Mo4fs/Cliques/Clusters/Sub‐networks
Loops
Chains
Parallels
Multi-input Single input
Interac-on Networks ‐ Basic Features
Single gene
– Regulators/Co‐regulators
– Upstream/Downstream elements in the network
– Global connec4vity/interconnec4vity
– Func4onal features
– Differen4ally expressed subnetworks
– One gene – one disease : bunch of genes – pathways
– Nextgen sequencing data
List of genes
Why Build/Analyze Interac-on Networks ?
Outline
• Introduc4on to Interac4on Networks
• Basic components of an interac4on network
• Types of interac4on networks
• Predic4ng Protein‐Protein Interac4on Networks
• Methods
» Logic and concept
• Available Interac4on data
• Integrated protein‐protein interac4on databases
• Searching for interac4on data
• Network Visualiza4on and Analysis tools
• Popular visualiza4on tools
• Network analysis
• Demonstra4on
• Predic4on of interac4on (PPI…?) network from microarray (ARACNE)
• Visualiza4on and analysis of the predicted network (Cytoscape)
How to Build Interac-on Networks ?
• Search/Retrieve from knowledge bases
• Predict from genome sequences
• Predict from “omics” data
• Predict from literature
• Integrate and analyze
Protein Engineering, Vol. 14, No. 9, 609-614, September 2001
Predic-on from genome sequences
• Gene neighbor (gene cluster, gene order)
• Gene fusion (Rose\a stone)
• Phylogene4c profiling
• Co‐evolu4on
• Mirror tree
Predic-on from “omics” data
• Co‐expression (Correla4on, Mutual Informa4on)
• Integrated (Classifica4on)
• Literature mining (Natural Language Processing)
Outline
• Introduc4on to Interac4on Networks
• Basic components of an interac4on network
• Types of interac4on networks
• Predic4ng Protein‐Protein Interac4on Networks
• Methods
» Logic and concept
• Available Interac4on data
• Integrated protein‐protein interac4on databases
• Searching for interac4on data
• Network Visualiza4on and Analysis tools
• Popular visualiza4on tools
• Network analysis
• Demonstra4on
• Predic4on of interac4on (PPI…?) network from microarray (ARACNE)
• Visualiza4on and analysis of the predicted network (Cytoscape)
Available Interac-on Data
• MINT
• Molecular Interac4on Database
• BIND
• Biomolecular Interac4on Network Database
• DIP
• Database of Interac4ng Proteins
• IntAct
• InterAc4on Database at EBI
IP3Rs
• Inositol triphosphate receptor
• ip3r1
• ip3r2
• ip3r3
» Calcium ion channels
» ER
• s4m1 (stromal interac4on molecule 1)
» PM
» Calcium sensor protein
• orai1 (calcium release ac4vated calcium modulator)
» PM
» Accessory protein downstream of s4m1
Searching for Interac-on Data
STRING
IPA
IPA
Outline
• Introduc4on to Interac4on Networks
• Basic components of an interac4on network
• Types of interac4on networks
• Predic4ng Protein‐Protein Interac4on Networks
• Methods
» Logic and concept
• Available Interac4on data
• Integrated protein‐protein interac4on databases
• Searching for interac4on data
• Network Visualiza4on and Analysis tools
• Popular visualiza4on tools
• Network analysis
• Demonstra4on
• Predic4on of interac4on (PPI…?) network from microarray (ARACNE)
• Visualiza4on and analysis of the predicted network (Cytoscape)
Analysis Tools
• Phunkee (Pairing subgraphs Using Network Environment Equivalence – finds
similar subnets)
• mfinder (mo4f detec4on)
• MAVisto (Mo4f Analysis and Visualiza4on tool – explora4on of mo4fs)
• GraphMatch (Search for similar sub‐nets)
• NeAT (Network Analysis Tools – mo4f finding, node sta4s4cs)
• Cfinder (Finds clusters – dense group of nodes)
• NetworkBLAST (Compares mul4ple networks to infer complexes & paths)
Outline
• Introduc4on to Interac4on Networks
• Basic components of an interac4on network
• Types of interac4on networks
• Predic4ng Protein‐Protein Interac4on Networks
• Methods
» Logic and concept
• Available Interac4on data
• Integrated protein‐protein interac4on databases
• Searching for interac4on data
• Network Visualiza4on and Analysis tools
• Popular visualiza4on tools
• Network analysis
• Demonstra4on
• Predic4on of interac4on (PPI…?) network from microarray (ARACNE)
• Visualiza4on and analysis of the predicted network (Cytoscape)
PPI Predic-on Using Microarray Data
• Co‐expression concept
• Correla4on Coefficient
» SIMoNE (Sta4s4cal Inference for Modular Networks) ‐ R
• Mutual Informa4on
» Reference Networks
» ARACNE (Algorithm for Reconstruc4on of Accurate Cellular
Networks) – R, geWorkbench
» CLR (Context Likelihood of Relatedness) – R
» MRNET (Maximum Relevance/Minimum Redundancy) – R
» MONET (Modularized NETwork Learning) ‐ Cytoscape
• Bayesian Network
PPI Predic-on Using Microarray Data
• Melanoma metastasis
• 83 samples
• Affymetrix
• GEO
• ARACNE
• geWorkbench
• IP3R1, IP3R2, IP3R3, STIM1, ORAI1
GML File
Predicted PPI Network
• Could form a complex
• Could be func4onally associated
• Could be involved in a same metabolic pathway
• Could be involved in a specific signal transduc4on path
• False posi4ve
Visualiza-on and Analysis Using Cytoscape
• Cytoscape
• Opensource
• Works in Windows, Linux, Mac
• One of the first developed tools
• Great number of PLUGINS
• Excellent help from community