P400 protein is one of the major substrates for Ca2+/calmodulin-dependent protein kinase II in the postsynaptic density-enriched fraction isolated from rat cerebral cortex, hippocampus and cerebellum.
Concanavalin A-binding glycoprotein with 250 K M(r) found in the postsynaptic density (PSD)-enriched preparation (or synaptic cytoskeleton) from rat cerebellum was identified with P400 protein from the physicochemical properties and enrichment in the cerebellum. Proteins homologous to the cerebellar 250 K M(r) protein occurred in the PSD-enriched preparations from rat cerebral cortex and from hippocampus, although the contents in the preparations were very low. The 250 K M(r) proteins in the PSD-enriched preparations from cerebellum and from cerebrum were highly phosphorylated by Ca2+/calmodulin (CaM)-dependent protein kinase II. The protein of synaptic plasma membrane (SPM) and PSD-enriched fractions prepared from cerebral cortex were not phosphorylated by the cAMP-dependent protein kinase endogenous to the fractions, whereas the protein from cerebellum was done in SPM and PSD-enriched fractions. The facts suggest that P400 or P400-like protein is closely associated with Ca2+/CaM-dependent protein kinase II in the PSD-enriched preparations, especially in the preparation from cerebral cortex. Phosphorylation of the protein by Ca2+/CaM-dependent protein kinase II may play an important role in the postsynaptic function in both cerebellum and at least in some areas of cerebrum.
Suzuki
T
T
Department of Biochemistry, Nagoya City University Medical School, Japan.
Abe-Dohmae
S
S
Tanaka
R
R
D000818:Animals; D015220:Calcium Channels; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002458:Cell Fractionation; D002531:Cerebellum / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006624:Hippocampus / Q000378:metabolism*; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008562:Membrane Glycoproteins / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D009928:Organ Specificity; D010449:Peptide Mapping; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism; D010766:Phosphorylation; D016548:Prosencephalon / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear; D013347:Subcellular Fractions / Q000378:metabolism; D013379:Substrate Specificity; D013569:Synapses / Q000502:physiology
D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; C488910:Itpr1 protein, rat; D008562:Membrane Glycoproteins; D010750:Phosphoproteins; D018160:Receptors, Cytoplasmic and Nuclear; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases