Website Review: pathway databases

Following on from the profile of web resources for protein-protein interactions in our last issue, we present a survey of pathway databases. The resources available have, in the past, been mainly concerned with metabolic pathways, which are in general, better characterised. However, the number of resources featuring regulatory pathways, or networks, has been increasing for some time. This area has great potential to evolve towards a more complex understanding of the networks in operation inside cells, sometimes referred to as systems (or integrative) biology, but this will require databases that encode the underlying theories and allow the integration of other datasets, such as protein and mRNA profiling results, rather than simple graphical representations of pathways. Eventually, this could lead to the ability to predict flux through pathways, and the effects of knocking out a gene in a network.