Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.17 (CaMKII)
 4,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have studied the subcellular distribution of phosphoproteins in intact hippocampal slices and examined factors that regulate their phosphorylation and dephosphorylation in situ. The presence of Ca2+ in slice equilibration and prelabeling buffers and high-K+-induced depolarization markedly increased 32Pi incorporation into endogenous proteins. Ca2+-stimulatory effects were significantly reduced by Ca2+-channel blockers and the calmodulin antagonist W-13. Certain proteins were dephosphorylated in situ, and their dephosphorylation was dependent on both Ca2+ and depolarization. A number of proteins phosphorylated in situ was similar to those previously characterized in synaptic fractions phosphorylated in vitro. Many phosphoproteins were identified on the basis of molecular weight, isoelectric point, immunoreactivity, and phosphopeptide mapping; these included the 87 kDa substrate of protein kinase C, synapsin I, the 50 and 60 kDa subunits of Ca2+/calmodulin-dependent protein kinase II (CKII), tubulin, B-50, the alpha-subunit of pyruvate dehydrogenase and myelin basic proteins. CKII phosphorylation in situ appeared similar but not identical to its in vitro counterpart. Phosphopeptide mapping analysis of in situ labeled substrate proteins indicated that cAMP-, Ca2+/calmodulin-, and Ca2+/phospholipid-dependent protein kinases were all active in slice preparations under basal conditions. Increased 32Pi labeling of hippocampal proteins following tissue depolarization appeared to be associated with increased activity of endogenous protein kinases since depolarization did not result in 32Pi-labeling of any new phosphoproteins.
 ...
PMID:In situ protein phosphorylation in hippocampal tissue slices. 255 35

The nervous tissue-specific protein B-50 (GAP-43), which has been implicated in the regulation of neurotransmitter release, is a member of a family of atypical calmodulin-binding proteins. To investigate to what extent calmodulin and the interaction between B-50 and calmodulin are involved in the mechanism of Ca(2+)-induced noradrenaline release, we introduced polyclonal anti-calmodulin antibodies, calmodulin, and the calmodulin antagonists trifluoperazine, W-7, calmidazolium, and polymyxin B into streptolysin-O-permeated synaptosomes prepared from rat cerebral cortex. Anti-calmodulin antibodies, which inhibited Ca2+/calmodulin-dependent protein kinase II autophosphorylation and calcineurin phosphatase activity, decreased Ca(2+)-induced nor-adrenaline release from permeated synaptosomes. Exogenous calmodulin failed to modulate release, indicating that if calmodulin is required for vesicle fusion it is still present in sufficient amounts in permeated synaptosomes. Although trifluoperazine, W-7, and calmidazolium inhibited Ca(2+)-induced release, they also strongly increased basal release. Polymyxin B potently inhibited Ca(2+)-induced noradrenaline release without affecting basal release. It is interesting that polymyxin B was also the only antagonist affecting the interaction between B-50 and calmodulin, thus lending further support to the hypothesis that B-50 serves as a local Ca(2+)-sensitive calmodulin store underneath the plasma membrane in the mechanism of neurotransmitter release. We conclude that calmodulin plays an important role in vesicular noradrenaline release, probably by activating Ca2+/calmodulin-dependent enzymes involved in the regulation of one or more steps in the release mechanism.
 ...
PMID:Evidence for a role of calmodulin in calcium-induced noradrenaline release from permeated synaptosomes: effects of calmodulin antibodies and antagonists. 878 20

The aim of the present study was to characterize the second messenger activated protein kinase and phosphatase systems in chick ciliary ganglion using biochemical and immunochemical techniques. Using synthetic peptide substrates cyclic-AMP-, cyclic-GMP-, Ca2+/calmodulin- and Ca2+/phospholipid-dependent protein kinase activities were detected in homogenates of ciliary ganglion dissected from 15-16-day-old embryos. Autophosphorylation of the alpha and beta subunits of Ca2+/calmodulin-dependent protein kinase II in the presence of Ca2+/calmodulin or 5 mM ZnSO4 was detected by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and autoradiography. Protein kinase C was shown to be present using a monoclonal antibody. Two cyclic-AMP binding proteins whose molecular weights corresponded to the regulatory subunits of cyclic AMP-dependent protein kinase (RI and RII) were detected in ciliary ganglia using 8-azido-cyclic-AMP. The most heavily labelled band following incubation with [gamma-32P]ATP under most conditions had an apparent molecular weight of 65,000 which corresponds to the chicken form of myristoylated alanine-rich C kinase substrate, a known substrate of protein kinase C. Another substrate for protein kinase C was a 45,000 molecular weight protein which was tentatively identified as neuromodulin (B-50/GAP-43). Although no endogenous substrate proteins for cyclic-GMP-dependent protein kinase were detected, protein kinase A strongly labelled a 40,000 molecular weight protein. Using 32P(i)-labelled glycogen phosphorylase, protein phosphatases 1 and 2A were identified in ciliary ganglia homogenates at levels which were indistinguishable from forebrain at the same age. The major endogenous protein substrates in ciliary ganglion homogenates from 15-16-day-old embryos were also labelled to a similar extent in homogenates of ciliary ganglia from newly hatched chickens. Intact ciliary ganglia remained viable for several hours after dissection and, after incubation with 32P(i), responded to phorbol ester stimulation by an increased endogenous phosphorylation of several proteins, but especially myristoylated alanine-rich C kinase substrate. These results represent the first systematic characterization of the protein phosphorylation systems in chicken ciliary ganglion and provide a basis for future studies on the biochemical mechanisms responsible for regulating synaptic transmission in this tissue.
 ...
PMID:Characterization of protein kinase and phosphatase systems in chick ciliary ganglion. 884 61

Mice and rats have a period of rapid growth and development that occurs postnatally, while in humans the corresponding period is perinatal. This gives us the opportunity to study direct effects of chemicals during developmental processes of the central nervous system (CNS) in murine animals. Mammals have a marked period of rapid brain growth and development, the brain growth spurt (BGS), which is postnatal in mice and rats, spanning the first 3-4 weeks of life and reaching its peak around postnatal day 10. The proteins synaptophysin and tau are involved in developmental processes in the nervous system during the BGS in mice. One class of flame retardants, polybrominated diphenyl ethers (PBDEs), is present and increasing in the environment and in human milk, which is also true for the only congener still in use, decabrominated diphenyl ether (2,2',3,3',4,4',5,5',6,6'-decaBDE, PBDE 209). The present study was divided into two parts (a) the neonatal ontogeny of synaptophysin and tau and (b) the developmental neurotoxic effect of PBDE 209 on synaptophysin and tau during the neonatal ontogeny in mice. The level of synaptophysin measured on postnatal days 1, 3, 7, 10, 14, and 28, increased continuously during the neonatal period, while tau has a bell-shaped ontogeny curve that peaks between postnatal days 7 and 10. The effects of PBDE 209 on the developmental expression of synaptophysin and tau were examined in neonatal NMRI male mice, orally exposed on day 3 to 20.1mg PBDE 209/kg body weight. The animals were euthanized 7 days after exposure to PBDE 209 and levels of synaptophysin and tau were analyzed in the hippocampus and cerebral cortex. The protein analysis showed that synaptophysin had increased significantly in the hippocampus, but not in the cerebral cortex, in mice 7 days after exposure to PBDE 209. The analysis of protein levels showed no changes in tau in the hippocampus or cerebral cortex 7 days after exposure to PBDE 209 on postnatal day 3. A recent study shows that neonatal PBDE 209-exposure can affect levels of BDNF (brain-derived neurotrophic factor), CaMKII (Ca(2+)/calmodulin-dependent protein kinase II), and GAP-43 (growth associated protein 43), which are proteins that are important for normal brain development. The present study shows that PBDE 209 affects the level of synaptophysin in the developing brain, which further supports the recent findings that PBDE 209 can disturb components of normal brain maturation and act as a developmental neurotoxicological agent. Furthermore, this suggests that certain proteins involved in developmental processes can serve as markers of developmental neurotoxicity.
 ...
PMID:Neonatal ontogeny and neurotoxic effect of decabrominated diphenyl ether (PBDE 209) on levels of synaptophysin and tau. 1946 8