Sci. Signal., 25 October 2011 Vol. 4, Issue 196, p. eg9 [DOI: 10.1126/scisignal.2002601] EDITORIAL GUIDES Focus Issue: Recruiting Players for a Game of ERK Nancy R. Gough1* 1 Editor of Science Signaling, American Association for the Advancement of Science, 1200 New York Avenue, N.W., Washington, DC 20005, USA. Abstract: The extracellular signal–regulated kinase (ERK) pathway is one of the superfamily of mitogen-activated protein kinase pathways. Signals transmitted by this kinase cascade activate a pair of related proteins, ERK1 and ERK2. Research published in Science Signaling shows that, despite the wealth of knowledge about this pathway, previously unknown functions continue to...