MRC Protein Phosphorylation Unit, The Sir James Black Centre, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK. p.cohen@dundee.ac.uk
Cell-permeable chemical inhibitors have become invaluable reagents for the study of cellular regulation. In the present paper, using protein kinase inhibitors as the example, a set of criteria are described that should be met before any investigation using such compounds should be accepted for publication.