Biomaterial Database

Identification of a major autophosphorylation site on postsynaptic density-associated Ca2+/calmodulin-dependent protein kinase. 1994

A Dosemeci, and N Gollop, and H Jaffe

Laboratory of Neurobiology, NINDS, National Institutes of Health, Bethesda, Maryland 20892.

One of the most abundant proteins in postsynaptic densities is identical or very similar to the alpha-subunit of the Ca2+/calmodulin-dependent protein kinase II. Autophosphorylation of this protein in isolated postsynaptic densities was studied under various conditions, following inhibition of endogenous phosphatase activity with microcystin-LR. Phosphorylation accompanied by a shift in the enzyme's electrophoretic mobility was observed upon incubation with Ca2+ and calmodulin at 37 degrees C. Brief incubation with Ca2+ and calmodulin at 0 degrees C resulted in a low level of phosphorylation and no change in mobility. Following this limited Ca(2+)-dependent phosphorylation, however, a high level of phosphorylation could be achieved in the absence of Ca2+, upon incubation at 37 degrees C. Comparison of reverse-phase HPLC phosphopeptide elution profiles obtained following phosphorylation at 37 degrees C, in the presence and absence of Ca2+, as described above, showed differences, suggesting that certain distinct sites may be phosphorylated under each condition. A major phosphopeptide peak, however, with the amino acid sequence Met-Leu-Thr(P)-Ile-Asn-Pro-Ser-Lys was identified under both conditions. This sequence is identical to the predicted sequence containing Thr-253 of the Ca2+/calmodulin-dependent protein kinase II. The results suggest that phosphorylation at Thr-253 requires an initial Ca(2+)-dependent phosphorylation, which may be at a different site, but does not depend on the continued presence of Ca2+ to proceed. The observed mode of regulation of autophosphorylation at Thr-253 appears to be unique to the postsynaptic density-associated enzyme.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D010449	Peptide Mapping	Analysis of PEPTIDES that are generated from the digestion or fragmentation of a protein or mixture of PROTEINS, by ELECTROPHORESIS; CHROMATOGRAPHY; or MASS SPECTROMETRY. The resulting peptide fingerprints are analyzed for a variety of purposes including the identification of the proteins in a sample, GENETIC POLYMORPHISMS, patterns of gene expression, and patterns diagnostic for diseases.	Fingerprints, Peptide,Peptide Fingerprinting,Protein Fingerprinting,Fingerprints, Protein,Fingerprint, Peptide,Fingerprint, Protein,Fingerprinting, Peptide,Fingerprinting, Protein,Mapping, Peptide,Peptide Fingerprint,Peptide Fingerprints,Protein Fingerprint,Protein Fingerprints
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002147	Calmodulin	A heat-stable, low-molecular-weight activator protein found mainly in the brain and heart. The binding of calcium ions to this protein allows this protein to bind to cyclic nucleotide phosphodiesterases and to adenyl cyclase with subsequent activation. Thereby this protein modulates cyclic AMP and cyclic GMP levels.	Calcium-Dependent Activator Protein,Calcium-Dependent Regulator,Bovine Activator Protein,Cyclic AMP-Phosphodiesterase Activator,Phosphodiesterase Activating Factor,Phosphodiesterase Activator Protein,Phosphodiesterase Protein Activator,Regulator, Calcium-Dependent,AMP-Phosphodiesterase Activator, Cyclic,Activating Factor, Phosphodiesterase,Activator Protein, Bovine,Activator Protein, Calcium-Dependent,Activator Protein, Phosphodiesterase,Activator, Cyclic AMP-Phosphodiesterase,Activator, Phosphodiesterase Protein,Calcium Dependent Activator Protein,Calcium Dependent Regulator,Cyclic AMP Phosphodiesterase Activator,Factor, Phosphodiesterase Activating,Protein Activator, Phosphodiesterase,Protein, Bovine Activator,Protein, Calcium-Dependent Activator,Protein, Phosphodiesterase Activator,Regulator, Calcium Dependent
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013569	Synapses	Specialized junctions at which a neuron communicates with a target cell. At classical synapses, a neuron's presynaptic terminal releases a chemical transmitter stored in synaptic vesicles which diffuses across a narrow synaptic cleft and activates receptors on the postsynaptic membrane of the target cell. The target may be a dendrite, cell body, or axon of another neuron, or a specialized region of a muscle or secretory cell. Neurons may also communicate via direct electrical coupling with ELECTRICAL SYNAPSES. Several other non-synaptic chemical or electric signal transmitting processes occur via extracellular mediated interactions.	Synapse