Oligomerization states of the association domain and the holoenyzme of Ca2+/CaM kinase II.Rosenberg, O.S., Deindl, S., Comolli, L.R., Hoelz, A., Downing, K.H., Nairn, A.C., Kuriyan, J.
(2006) Febs J. 273: 682-694
- PubMed: 16441656
- DOI: 10.1111/j.1742-4658.2005.05088.x
- PubMed Abstract:
Ca2+/calmodulin activated protein kinase II (CaMKII) is an oligomeric protein kinase with a unique holoenyzme architecture. The subunits of CaMKII are bound together into the holoenzyme by the association domain, a C-terminal region of approximately ...
Ca2+/calmodulin activated protein kinase II (CaMKII) is an oligomeric protein kinase with a unique holoenyzme architecture. The subunits of CaMKII are bound together into the holoenzyme by the association domain, a C-terminal region of approximately 140 residues in the CaMKII polypeptide. Single particle analyses of electron micrographs have suggested previously that the holoenyzme forms a dodecamer that contains two stacked 6-fold symmetric rings. In contrast, a recent crystal structure of the isolated association domain of mouse CaMKIIalpha has revealed a tetradecameric assembly with two stacked 7-fold symmetric rings. In this study, we have determined the crystal structure of the Caenorhabditis elegans CaMKII association domain and it too forms a tetradecamer. We also show by electron microscopy that in its fully assembled form the CaMKII holoenzyme is a dodecamer but without the kinase domains, either from expression of the isolated association domain in bacteria or following their removal by proteolysis, the association domains form a tetradecamer. We speculate that the holoenzyme is held in its 6-fold symmetric state by the interactions of the N-terminal approximately 1-335 residues and that the removal of this region allows the association domain to convert into a more stable 7-fold symmetric form.
Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3202, USA.