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Antibody specific for the Thr-286-autophosphorylated alpha subunit of Ca2+/calmodulin-dependent protein kinase II
T Suzuki1, K Okumura-Noji, A Ogura
1Department of Biochemistry, Nagoya City University Medical School, Japan.
Abstract:
We report the production of an antibody specific for Ca2+/calmodulin-dependent protein kinase II (CaM-KII) autophosphorylated only at Thr-286 of the alpha subunit. Peptide Y-66 [sequence MHRQETVDC (Met-281 to Cys-289 of alpha subunit of CaM-KII)] was synthesized and phosphorylated by the CaM-KII endogenous to synaptic cytoskeleton (postsynaptic density-enriched fraction); the phosphorylated amino acid residue threonine corresponds to Thr-286 in the kinase alpha subunit. The phosphorylated Y-66 peptide was separated from the unphosphorylated peptide by HPLC and used as an immunogen after being coupled to hemocyanin. The antibodies that reacted with hemocyanin and unphosphorylated Y-66 peptide were adsorbed, and then IgG was purified. ELISA proved that the IgG obtained reacted specifically with phosphorylated Y-66 peptide. Immunoblot analysis showed that the antibody reacted specifically to the autophosphorylated CaM-KII both in purified and synaptic cytoskeleton-associated form. Appearance of CaM-KII subunits immunoreactive to anti-phosphorylated Y-66 antibody paralleled the generation of Ca(2+)-independent kinase activity. Immunocytochemical experiments clearly showed expression of the Thr-286- or Thr-287-autophosphorylated form of CaM-KII in cultured hippocampal cells treated with N-methyl-D-aspartate. Thus, this antibody could be extremely useful for studying the biological functions of CaM-KII.
Insights
Researchers developed a specific antibody for Ca2+/calmodulin-dependent protein kinase II (CaM-KII) autophosphorylated at Thr-286. This new tool aids in studying CaM-KII
Area of Science:
- Neuroscience
- Molecular Biology
- Biochemistry
Background:
- Ca2+/calmodulin-dependent protein kinase II (CaM-KII) plays a crucial role in synaptic plasticity and memory formation.
- Autophosphorylation of CaM-KII at Thr-286 is critical for its sustained activity and cellular functions.
- Developing specific tools to detect the active, autophosphorylated form of CaM-KII is essential for understanding its biological roles.
Purpose of the Study:
- To generate and characterize a novel antibody that specifically recognizes CaM-KII autophosphorylated at Thr-286.
- To validate the specificity and utility of this antibody in biochemical and cellular assays.
- To investigate the biological significance of CaM-KII autophosphorylation in neuronal signaling.
Main Methods:
- Synthesis of a peptide (Y-66) corresponding to residues 281-289 of CaM-KII alpha subunit.
- In vitro phosphorylation of the Y-66 peptide by CaM-KII and subsequent purification of the phosphorylated peptide.
- Coupling of the phosphorylated peptide to hemocyanin for use as an immunogen.
- Adsorption of antibodies against non-specific targets (hemocyanin, unphosphorylated peptide).
- Purification of specific IgG antibodies.
- Enzyme-Linked Immunosorbent Assay (ELISA) to confirm antibody specificity.
- Immunoblot analysis to detect autophosphorylated CaM-KII in purified and synaptic fractions.
- Immunocytochemistry to visualize the localization of autophosphorylated CaM-KII in cultured hippocampal neurons.
Main Results:
- A highly specific antibody was successfully produced, recognizing CaM-KII autophosphorylated exclusively at Thr-286.
- ELISA confirmed the antibody's specific reactivity with the phosphorylated peptide.
- Immunoblot analysis demonstrated the antibody's ability to detect autophosphorylated CaM-KII in both purified and synaptic cytoskeleton-associated forms.
- The appearance of immunoreactive CaM-KII subunits correlated with the generation of Ca(2+)-independent kinase activity.
- Immunocytochemistry revealed the expression of Thr-286/Thr-287 autophosphorylated CaM-KII in N-methyl-D-aspartate-treated hippocampal cells.
Conclusions:
- The developed antibody provides a specific and reliable tool for detecting the active, autophosphorylated form of CaM-KII.
- This antibody facilitates the study of CaM-KII's role in cellular processes, particularly in response to stimuli like N-methyl-D-aspartate.
- The findings pave the way for further research into the biological functions and signaling pathways involving CaM-KII autophosphorylation.