New Feature. In response to the COVID-19 pandemic, Reactome is fast-tracking the annotation of Human Coronavirus infection pathways in collaboration with the COVID-19 Disease Map group. V73 includes descriptions of the SARS-CoV-1 Infection pathway as well as Potential therapeutics for SARS. In the coming months, we will use these descriptions as starting points to annotate the SARS-CoV-2 infection pathway and interactions with host proteins that affect the severity of COVID-19 disease.

New and Updated Pathways. Other topics with new or revised pathways in V73 include Cell Cycle (Inhibition of DNA recombination at telomeres, Telomere Maintenance), Disease (Aberrant regulation of mitotic cell cycle due to RB1 defects, Defects of contact activation system (CAS) and kallikrein/kinin system (KKS), Oncogenic MAPK signaling, Signaling by KIT in disease, and Signal Transduction (RAF/MAP kinase cascade, RAS processing).

New and Updated Illustrations. Illustrations with embedded navigation features have been added for Nervous system development, Defects in vitamin and cofactor metabolism, Diseases of Carbohydrate metabolism, Diseases of Metabolism, and SARS-CoV infections.  New static illustrations are now available for Costimulation by the CD28 family, CD28 co-stimulation, Downstream TCR signaling, G2/M DNA damage checkpoint, G2/M DNA replication checkpoint, Generation of second messenger molecules, p53-Independent DNA Damage Response, Phosphorylation of CD3 and TCR zeta chains, SARS-CoV-1 Infection, and Translocation of ZAP-70 to Immunological synapse.

Thanks to our Contributors. Marcio Luis Acencio, Frederick A Dick, Alfonso García-Valverde, Evripidis Gavathiotis, Makoto T Hayashi, Alexander Mazein, Daniel Pilco-Janeta, Cesar Serrano, Brian Shoichet, and Bin Zhang are our external reviewers.

Annotation Statistics. Reactome comprises 13,248 human reactions organized into 2,423 pathways involving 11,111 proteins and modified forms of proteins encoded by 10,923 different human genes, 12,728 complexes, 1,869 small molecules, and 369 drugs. These annotations are supported by 32,150 literature references. We have projected these reactions onto 81,835 orthologous proteins, creating 18,654 orthologous pathways in 15 non-human species. Version 73 has annotations for 2,620 protein variants (mutated proteins) and their post-translationally modified forms, derived from 327 proteins, which have been used to annotate disease-specific 1,297 reactions and 605 pathways.

Tools and Data. Our services and software tools are designed for biologists, bioinformaticians, and software developers. Pathway data is available to view in our Pathway Browser, to analyze your own dataset, to download, and to access programmatically through our Content and Analysis Services. The ReactomeFIViz app for Cytoscape provides tools to find pathways and network patterns related to cancer and other types of diseases.

Documentation and Training. Visit our online User Guide to access documentation supporting pathway analysis of experimental data. The Developer's Zone provides detailed documentation regarding our software, tools, and web services. Training and learning materials can be found here.

About the Reactome Project. Reactome is a collaboration between groups at the Ontario Institute for Cancer Research, Oregon Health and Science University, New York University Langone Medical Center, and The European Bioinformatics Institute. Reactome annotation files and interaction data derived from Reactome are distributed under a Creative Commons Public Domain (CC0 1.0 Universal) Licence. A Creative Commons Attribution 4.0 International (CC BY 4.0) Licence will apply to all software and code, database data dumps, and Pathway Illustrations (Enhanced High-Level Diagrams), Icon Library, Art and Branding Materials. A full description of the new and updated content is available on the Reactome website.

Follow us on Twitter: @reactome to get frequent updates about new and updated pathways, feature updates, and more!

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