• http://pid.nci.nih.gov

In the era of systems biology and high-throughput data, several databases of interaction maps are currently available. If you are looking for a carefully designed web-search interface that supports simple browsing across predefined pathways, the construction of larger networks, and analysis and visualization of lists of targeted molecules in the context of predefined and novel networks, then check out the Pathway Interaction Database (PID).

PID is a highly structured, curated collection of information about known biomolecular interactions and cellular processes assembled into signalling pathways. This database is a collaborative project between the US National Cancer Institute (NCI) and Nature Publishing Group. “The vision was ... to create a database that would support novel approaches to analysing pathways and facilitate the identification of candidate molecular targets for cancer therapies.”

PID is designed for biologists and bioinformaticians alike and provides high-quality information about signalling pathways in human cells. It also provides a set of tools to allow the pathways to be explored, visualized and mined. Scientists can browse PID as an online encyclopaedia, run computational analyses or combine these two approaches.

Currently, PID contains data from two sources — the 'NCI–Nature-curated' and peer-reviewed data, which comprises more than 45 pathways, 2500 proteins, 2000 complexes and 2500 interactions and data that were imported from the BioCarta web site before June 2004.

Other features include an editorial section with specially written synopses of recent important research articles in areas related to cancer research, the commissioned Bioinformatics Primers that provide practical advice on how to make the most of other relevant online resources, and the monthly email alert to stay informed about new content.