Detection of Phospho-CaM Kinase II (T286) by Western Blot. Western Blot of rat brain tissue lysate showing specific immunolabeling of the ~50 kDa alpha -CaMKII subunit phosphorylated at T286 and the ~60 kDa beta -CaMKII subunit phosphorylated at T287 (Control). The phosphospecificity of this labeling is demonstrated by treatment with 1200 U of lambda Phosphatase ( lambda -PPase) for 30 minutes before being exposed to the anti-phospho-CaMKII (T286). The immunolabeling is completely eliminated by treatment with lambda -PPase.
Preparation and Storage
The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage
For long-term storage, ≤ -20° C is recommended. Product is stable at ≤ -20° C for at least 1 year.
Background: CaM Kinase II
Calmodulin Kinase II (CaMKII) is a 500 kDa, 8-12 subunit multimer that belongs to the Ser/Thr protein kinase family. It is ubiquitously expressed and interacts with a very diverse group of substrates. In rat, there are four possible subunits/isozymes ( alpha, beta, gamma, δ) that vary from 480-540 amino acids in length. The alpha - and beta -isozymes predominate in the brain. Each subunit contains a catalytic, autoregulatory, and subunit-association domain. The enzyme complex is inactive, due to the association of an internal pseudosubstrate motif with each subunit’s catalytic domain. CaMKII is regulated by calmodulin (CaM), an intracellular receptor for calcium. Following an influx of calcium, two Ca++-CaM complexes interact with inactive CaMKII at the autoregulatory site of two adjacent CaMKII subunits. This dissociates the catalytic site from the pseudosubstrate motif, allowing for the auto(cross)-phosphorylation of T286 on one alpha -subunit (T287 on a beta -subunit) by the catalytic site on an adjacent subunit. The T286 phosphorylation event blocks a reassociation of the catalytic domain with the internal pseudosubstrate motif, resulting in prolonged activation. Once activated, an autoinhibitory program ensues. The dissociation of Ca++-CaM from CaMKII exposes a Thr at position 305. CaMKII autophosphorylation of Thr at this site downregulates existing CaMKII activity.
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