27 April 2010
Vol 3, Issue 119

About The Cover

Cover image expansion

Online Cover This week's issue features a Research Article in which a mutant form of the atypical protein kinase CASK [calcium/calmodulin (CaM)–activated serine-threonine kinase] was used to investigate the role of Mg2+ in facilitating kinase catalytic activity. Phylogenetic analyses indicated that CASK, which—unlike conventional kinases—doesn't require Mg2+ for its catalytic activity, evolved from a Mg2+-dependent kinase and suggested that CASK's loss of Mg2+-dependent catalytic activity may have enabled the development of a mechanism through which it could be regulated by localized changes in divalent cation concentration. The image shows the crystal structure of CASK in the foreground (PDB: 3C0H) and a typical calcium/calmodulin-regulated kinase, CaMKII, in the background (PDB: 2BDW). [Image: Chris Bickel, AAAS]