Structure of the Autoinhibited Kinase Domain of CaMKII and SAXS Analysis of the Holoenzyme
Rosenberg, O.S., Deindl, S., Sung, R.-J., Nairn, A.C., Kuriyan, J.(2005) Cell 123: 849-860
- PubMed: 16325579 
- DOI: https://doi.org/10.1016/j.cell.2005.10.029
- Primary Citation of Related Structures:  
2BDW - PubMed Abstract: 
Ca2+/calmodulin-dependent protein kinase-II (CaMKII) is unique among protein kinases for its dodecameric assembly and its complex response to Ca2+. The crystal structure of the autoinhibited kinase domain of CaMKII, determined at 1.8 A resolution, reveals an unexpected dimeric organization in which the calmodulin-responsive regulatory segments form a coiled-coil strut that blocks peptide and ATP binding to the otherwise intrinsically active kinase domains. A threonine residue in the regulatory segment, which when phosphorylated renders CaMKII calmodulin independent, is held apart from the catalytic sites by the organization of the dimer. This ensures a strict Ca2+ dependence for initial activation. The structure of the kinase dimer, when combined with small-angle X-ray scattering data for the holoenzyme, suggests that inactive CaMKII forms tightly packed autoinhibited assemblies that convert upon activation into clusters of loosely tethered and independent kinase domains.
Organizational Affiliation: 
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.