Orienteering strategies for a signaling maze.

T his joint Special Issue by Science's Signal Trans-duction Knowledge Environment (STKE) and Science presents important developments in the sprawling field of signal transduction. (Signal transduction refers to the processes by which cells perceive their environment or internal status and react to such stimuli with appropriate physiological responses.) The Viewpoints in this issue of Science provide authoritative syntheses that are accessible to the nonspecial-ist, explaining what a signaling pathway does and why it does it. Furthermore, this issue highlights new ways in which Sci-ence's STKE is working with authors to efficiently convey complex information. At Science's STKE, readers can delve deeper into the topic and take advantage of special electronic features, particularly the " Connections Map " database in which the details of the signaling pathway are dynamically displayed and annotated. (STKE is the first of a series of Knowledge Environments published by AAAS. These electronic publications gather a comprehensive set of resources to enhance access to information in a fast-moving field like cell signaling.) Advances in information technology are required in the biological sciences to cope with the amount and complexity of information that must be handled in the postgenome era. Thus, Science's STKE has explored a new way of organizing, storing, and communicating the essence of our current understanding of signaling mechanisms. The Connections Maps are an interface to a database of authoritative information on signaling molecules and their relations with one another. * The reader accesses information through a Web interface that displays dynamically generated maps of the pathways (created in real time from the database, so there is no lag while an artist works on updating a drawing). Symbols in the maps represent signaling components or the relations between them, and users can access more information just by clicking on these symbols. The Connections Maps are identified as either " canoni-cal " or " specific. " The canonical maps show the generic pathway module—a sort of consensus view. This type of pathway is useful for understanding the general signaling principles of the pathway and how modules are adapted to distinct functions, but are not intended to represent the situation in a real cell at a particular point in time. The specific pathways, on the other hand, depict real molecules and only those relations that are experimentally supported for a particular species, tissue, and cell type. Thus, components in the specific pathways can be linked to a …