An allosteric model of calmodulin explains differential activation of PP2B and CaMKII

作者：Stefan Melanie I; Edelstein Stuart J; Le Novere Nicolas^*

来源：Proceedings of the National Academy of Sciences of the United States of America, 2008, 105(31): 10768-10773.

DOI：10.1073/pnas.0804672105

• allostery
• synaptic plasticity
• calcium binding
• cooperativity
• conformational transition

Calmodulin plays a vital role in mediating bidirectional synaptic plasticity by activating either calcium/calmodulin-dependent protein kinase II (CaMKII) or protein phosphatase 2B (PP2B) at different calcium concentrations. We propose an allosteric model for calmodulin activation, in which binding to calcium facilitates the transition between a low-affinity [tense (7)] and a high-affinity [relaxed (R)] state. The four calcium-binding sites are assumed to be nonidentical. The model is consistent with previously reported experimental data for calcium binding to calmodulin. It also accounts for known properties of calmodulin that have been difficult to model so far, including the activity of nonsaturated forms of calmodulin (we predict the existence of open conformations in the absence of calcium), an increase in calcium affinity once calmodulin is bound to a target, and the differential activation of CaMKII and PP2B depending on calcium concentration.

• 出版日期2008-8-5