A sharper instrument for dissecting signalling events: a specific AGC kinase inhibitor.

Small-molecule inhibitors are now widely used to try to dissect regulatory signalling events. Many of these interfere with the function of protein kinases, often as part of signalling cascades. In addition to their utility as tools for the researcher, the long-term aspiration is that certain of these compounds may be useful as therapeutic agents for the treatment of conditions that arise from the dysregulation of specific signalling pathways. In this issue of the Biochemical Journal, Sapkota and colleagues report the identification and initial validation of a compound that inhibits the RSK (p90 ribosomal S6 kinase) group of protein kinases, which are members of an important family of kinases (the 'AGC kinases') that have overlapping specificities.