PathwayPilot: A User-Friendly Tool for Visualizing and Navigating Metabolic Pathways.

Metaproteomics, the study of collective proteomes in environmental communities, plays a crucial role in understanding microbial functionalities affecting ecosystems and human health. Pathway analysis offers structured insights into the biochemical processes within these communities. However, no existing tool effectively combines pathway analysis with peptide- or protein-level data. We here introduce PathwayPilot, a web-based application designed to improve metaproteomic data analysis by integrating pathway analysis with peptide- and protein-level data, filling a critical gap in current metaproteomics bioinformatics tools. By allowing users to compare functional annotations across different samples or multiple organisms within a sample, PathwayPilot provides valuable insights into microbial functions. In the re-analysis of a case study examining the effects of caloric restriction on gut microbiota, the tool successfully identified shifts in enzyme expressions linked to short-chain fatty acid biosynthesis, aligning with its original findings. PathwayPilot's user-friendly interface and robust capabilities make it a significant advancement in metaproteomics, with potential for widespread application in microbial ecology and health sciences. All code is open source under the Apache2 license and is available at https://pathwaypilot.ugent.be.