APPINetwork

APPINetwork constructs and analyzes protein-protein interaction (PPI) networks to enable comparative and functional studies of protein interactions across species.

Key Features:

• Cross-Species Compatibility: Builds and analyzes PPI networks for proteins from any organism provided relevant data are available in source databases.
• First-Order and Second-Order Network Construction: Supports construction of first-order networks mapping direct interactions and second-order networks centered on proteins of interest or complex subunits.
• Integration with Multiple Databases: Imports PPI data from IntAct, BioGRID, iRefIndex and private databases to combine diverse data sources.
• Data Standardization: Standardizes protein identifiers across databases to ensure consistency in constructed networks.
• Analytical Capabilities: Identifies communities of proteins, detects assembly intermediates of protein complexes, and reports the number and types of experiments supporting each PPI along with literature references.
• Multi-Language Implementation: Implements core functionality in R with supplementary C and Python 3 scripts, including scripts for identifying proteins involved in biological processes and formatting BioGRID data files.

Scientific Applications:

• Functional Module Identification: Detects sub-networks and communities corresponding to functional modules and biological processes.
• Hub Protein Identification: Identifies key hub proteins within PPI networks that may coordinate cellular functions.
• Protein Complex Assembly Studies: Analyzes assembly intermediates and subunit relationships within protein complexes.
• Comparative PPI Analysis: Enables cross-species comparison of interaction networks when source data are available.

Methodology:

Implemented as an R package with supplementary C and Python 3 scripts; imports PPI data from IntAct, BioGRID, iRefIndex and private databases, formats BioGRID data files, standardizes protein identifiers, constructs first-order and second-order networks, identifies protein communities and assembly intermediates, and reports numbers and types of supporting experiments with literature references.