Differential regulation by ATP versus ADP further links CaMKII aggregation to ischemic conditions.
CaMKII, a major mediator of synaptic plasticity, forms extra-synaptic clusters under ischemic conditions. This study further supports self-aggregation of CaMKII holoenzymes as the underlying mechanism. Aggregation in vitro was promoted by mimicking ischemic conditions: low pH (6.8 or less), Ca(2+) (and calmodulin), and low ATP and/or high ADP concentration. Mutational analysis showed that high ATP prevented aggregation by a mechanism involving T286 auto-phosphorylation, and indicated requirement for nucleotide binding but not auto-phosphorylation also for extra-synaptic clustering within neurons. These results clarify a previously apparent paradox in the nucleotide and phosphorylation requirement of aggregation, and support a mechanism that involves inter-holoenzyme T286-region/T-site interaction.
Department of Pharmacology, University of Colorado Denver, Aurora, CO 80045, United States.
Rebekah S
RS
Vest
Heather
H
O'Leary
K Ulrich
KU
Bayer
D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D015687:Cell Hypoxia; D002460:Cell Line; D002478:Cells, Cultured; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007511:Ischemia / Q000503:physiopathology; D008958:Models, Molecular; D009154:Mutation; D009474:Neurons / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D018411:Spodoptera
D002147:Calmodulin; D049452:Green Fluorescent Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D002118:Calcium