Humans ; Calcium/metabolism* ; Calmodulin ; Arrhythmias, Cardiac ; Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism* ; Myocytes, Cardiac/metabolism* ; Phosphorylation

OBJECTIVE: To investigate the effect of calmodulin (CaM) and its mutants on binding to voltage-gated Na channel isoleucine-glutamine domain (Na1.2 IQ). METHODS: The cDNA of Na1.2 IQ was constructed by PCR technique, CaM mutants CaM, CaM and CaM were constructed with Quickchange site-directed mutagenesis kit (QIAGEN). The binding of Na1.2 IQ to CaM and CaM mutants under calcium and calcium free conditions were detected by pull-down assay. RESULTS: Na1.2 IQ and CaM were bound to each other at different calcium concentrations, while GST alone did not bind to CaM. The binding affinity of CaM and Na1.2 IQ at [Ca]-free was greater than that at 100 nmol/L [Ca] ( < 0.05). In the absence of calcium, the binding amount of CaM wild-type to Na1.2 IQ was greater than that of its mutant, and the binding affinity of CaM to Na1.2 IQ was the weakest among the three mutants ( < 0.05). CONCLUSIONS The binding ability of CaM and CaM mutants to Na1.2 IQ is Ca-dependent. This study has revealed a new mechanism of Na1.2 regulated by CaM, which would be useful for the study of ion channel related diseases.
Calcium ; metabolism ; Calmodulin ; genetics ; metabolism ; Mutation ; NAV1.2 Voltage-Gated Sodium Channel ; metabolism ; Protein Binding ; genetics

AIMTo investigate the resting [Ca2]i level and expression of calmodulin (CaM), calmodulin-dependent protein kinase II (CaMPKII) mRNA in hippocampal neurons of the mice with vascular dementia (VD) and their roles in the pathogenesis of VD.

METHODSThe mice were subjected for ischemia/reperfusion repeatedly on bilateral common carotid arteries by knots to establish the VD models. Animals with the sham-operation were taken as control group. The changes of behavior were observed through the step-down avoidance test and water maze test on the day 29, 30 after the operations. The hippocampal neurons were obtained immediately after mice were sacrificed and the resting [Ca2+]i was measured using laser scanning confocal microscopy with Fluo-3/AM as fluorescence indicator. RT-PCR technique was used to measure the mRNA expression of CaM, CaMPKII in hippocampal neurons.

RESULTS(1) The abilities of learning and memorizing in model group were inferior to those of sham-operation group( P < 0.05). (2) The resting [Ca2]i level in model group was significantly higher than sham-operation group (P < 0.05), while the expression of CaMmRNA, CaMPKIImRNA in VD group was significantly reduced than sham-operation group (P < 0.01).

CONCLUSIONOur study indicates that excessive resting[Ca2+ ]i level and lower CaM, CaMPKII expression in hippocampal neurons might participate in the pathogenesis of VD.

Animals ; Calcium ; analysis ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; genetics ; metabolism ; Calmodulin ; genetics ; metabolism ; Dementia, Vascular ; metabolism ; Hippocampus ; cytology ; metabolism ; Male ; Mice ; Mice, Inbred Strains ; Neurons ; metabolism ; RNA, Messenger ; genetics

RalA GTPase, a member of Ras superfamily proteins, shows alternative forms between the active GTP-binding and the inactive GDP-binding states. Ral-specific guanine nucleotide exchange factor such as RalGDS interacts with activated Ras and cooperates with Ras indicating that Ral can be activated through Ras signaling pathway. Another activation path for Ral are through Ca2+-dependent but Ras-independent manner. In this study, studies were carried out to examine possible effects of Ca2+ and calmodulin, Ca2+-binding protein, directly on the GTP/GDP-binding state to recombinant unprenylated GST-RalA proteins. The results showed that Ca2+ stimulated the binding of GTP to RalA, whereas it reduced the binding of GDP to RalA. However, it does not involve a high affinity association of Ca2+ with RalA. Ca2+/calmodulin stimulated the GTPase activity of RalA. These results indicate that Ca2+ alone activates RalA by stimulating GTP-binding to RalA and Ca2+/calmodulin inactivates RalA by increasing the activity of RalGTPase.
Animal ; Brain/metabolism ; Calcium/*metabolism ; Calmodulin/*metabolism ; GTP Phosphohydrolases/*metabolism ; Guanosine Diphosphate/metabolism ; Guanosine Triphosphate/*metabolism ; Rats ; Support, Non-U.S. Gov't ; Synaptosomes/metabolism

OBJECTIVETo explore effect of curcumin in different concentrations on learning and memory of senescence-accelerated mice (SAM) and their possible mechanisms.

METHODSMice were randomly divided into six groups: the SAMR1 normal control group, the SAMP8 model control group, the SAMP8 + solvent (the peanut oil) control group, SAMP8 + low, middle and high dose curcumin groups. Mice were gastrogavage for 25 successive days. On the next day of ending the experiment, changes of learning and memory in mice of each group were observed by Morris water maze. The hippocampal [Ca2+] was determined. Expressions of hippocampal calmodulin-dependent protein kinase II (CaMK II) and Calmodulin (CaM) mRNA were detected using Western blot and reverse transcription polymerase chain reaction (RT-PCR) respectively.

RESULTSThe latency to find the hidden platform was remarkably prolonged, the hippocampal [Ca2+]i was markedly increased, the expression of CaMK II in the hippocampal membrane and the level of hippocampal CaM mRNA were significantly reduced in the SAMP8-model control group (P < 0.05, P < 0.01). The latency to find the hidden platform was remarkably shortened in the SAMP8 + middle dose curcumin and the SAMP8 + high dose curcumin groups (P < 0.01). The hippocampal [Ca2+]i was markedly lowered, the expression of CaMK II in the hippocampal membrane and the level of hippocampal CaM mRNA obviously increased in the SAMP8 + low, middle and high dose curcumin groups (P < 0.05, P < 0.01).

CONCLUSIONCurcumin could improve learning and memory Ca2+/capacities of SAM by lowering hippocampal [Ca2+] overload, increase the hippocampal CaM mRNA level and CaMK II expression in the hippocampal dose-dependently.

Aging ; drug effects ; metabolism ; Animals ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; metabolism ; Calmodulin ; metabolism ; Curcumin ; pharmacology ; Hippocampus ; drug effects ; metabolism ; Maze Learning ; drug effects ; Memory ; drug effects ; Mice ; RNA, Messenger ; genetics

OBJECTIVETo reconstitute an Alzheimer's disease model by administering bradykinin (BK) or cyclosporine A (CSA) to the rat hippocampus.

METHODSBK or CSA was administered to the rat hippocampus using a stereotaxic apparatus. The behavior of the rats was observed with an electronic attack jump platform. The phosphorylation of Tau protein was examined through immunohistochemical assay.

RESULTSBehavior studies showed that an obvious disturbance in learning and memory was seen in BK injected rats.No obvious dysfunction was observed in CSA injected rats. The results obtained by immunohistochemical assay indicated that the staining of M4, 12E8, paired helical filament-1 (PHF-1) and calcium/calmodulin-dependent protein kinase II (CaMKII) was stronger, and that of Tau-1 was weaker in BK injected rats compared with the control group. We also found that the binding of M4 and PHF-1 but not 12E8 to Tau was significantly increased in CSA injected rats. As for BK injection, binding of Tau-1 to Tau was decreased after CSA injection.

CONCLUSIONTo our knowledge, this is the first data showing in vivo that the activation of CaMKII induces both Alzheimer-like Tau phosphorylation and behavioral disturbances.

Alzheimer Disease ; etiology ; Animals ; Bradykinin ; toxicity ; Calcium ; metabolism ; Calcium-Calmodulin-Dependent Protein Kinase Type 2 ; Calcium-Calmodulin-Dependent Protein Kinases ; metabolism ; Cyclosporine ; toxicity ; Disease Models, Animal ; Hippocampus ; drug effects ; metabolism ; Immunohistochemistry ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; tau Proteins ; analysis ; metabolism

AIMTo evaluate whether protein phosphorylation and dephosphorylation in nuclei play roles in the development of myocardial hypertrophy, distribution of protein kinases and phosphatases in cell fractions were determined.

METHODSThe model of hypertensive rat was established by abdominal aortic constriction. Velocity and isopyknic gradient centrifugation was employed to fractionate rat myocardium to membrane, cytosol and nuclei. Enzymatic methods were employed to determine kinases and phosphatases.

RESULTSCompare with control group, the activity of CaMK increased by 101.1% (P < 0.01) and 40.16% (P < 0.01) respectively in nuclear and membranous fractions, changed without significance in cytosolic fraction; the activity of calcineurin in nuclei increased by 43.57%, (P < 0.05), lightly changed without significance in membranous and cytosolic fractions.

CONCLUSIONNuclear translocation of CaMK and calcineurin, might play important roles on overload-induced cardiac hypertrophy.

Animals ; Calcineurin ; metabolism ; Calcium ; metabolism ; Calcium-Calmodulin-Dependent Protein Kinases ; metabolism ; Cardiomyopathy, Hypertrophic ; metabolism ; pathology ; physiopathology ; Cell Nucleus ; metabolism ; Male ; Rats ; Rats, Wistar

Genistein is a kind of isoflavone compounds， also called phytoestrogens， with clinical effects on cardiovascular disease， cancer and postmenopausal-related gynecological diseases， and also has the potentiality in the prevention and treatment of Alzheimer's disease(AD). In this study， the protective effect of genistein on Aβ₂₅₋₃₅-induced PC12 cell injury and effect on CaM-CaMKIV signaling pathway were observed to investigate its mechanism for AD. PC12 cells were cultured and then the safe concentration of genistein and the modeling concentration and optimal time point of administration of Aβ₂₅₋₃₅ were screened by MTT assay. After being pretreated with different concentrations of genistein(25， 50， 100 μmol·L⁻¹) on PC12 cells， the AD model of PC12 cells was induced by Aβ₂₅₋₃₅. Then the survival rate of cells was detected by MTT assay; morphological change of cells was observed under the inverted microscope， and apoptosis of cells was assessed by AO/EB fluorescence staining; the neuroprotective effects of genistein on AD cell model were observed and the optimal concentration of genistein was determined. Expressions of mRNA and protein levels of CaM， CaMKK， CaMKIV and tau were detected by qRT-PCR and Western blot assay， respectively. The results showed that as compared with the blank group， the cell survival rate was decreased; the cell damage and apoptosis were increased; and the expressions of mRNA and protein levels of CaM， CaMKK， CaMKIV and tau were increased in AD model group. Genistein could significantly improve the cell survival rate， reduce the cell damage and apoptosis of AD cell model， and significantly down-regulate the expressions of mRNA and protein levels of CaM， CaMKK， CaMKIV and tau of AD cell model. These results indicated that genistein has obviously neuroprotective effect on the AD cell model induced by Aβ₂₅₋₃₅， and the mechanism may be related to the down-regulation of CaM-CaMKIV signaling pathway and Tau protein expression.
Amyloid beta-Peptides ; Animals ; Apoptosis ; Calcium-Calmodulin-Dependent Protein Kinase Type 4 ; metabolism ; Calmodulin ; metabolism ; Cell Survival ; Genistein ; pharmacology ; PC12 Cells ; Peptide Fragments ; Protective Agents ; pharmacology ; Rats ; Signal Transduction ; drug effects

Alcoholic liver disease(ALD), with its increasing morbidity and mortality, has seriously and extensively affected the health of people worldwide. Methyl ferulic acid(MFA) has been proven to significantly inhibit alcohol-induced lipid production in L02 cells through the AMP-activated protein kinase(AMPK) pathway, but its in-depth mechanism remains unclear. This study aimed to further clarify the mechanism of MFA in improving lipid accumulation in L02 cells through the microRNA-378b(miR-378b)-mediated calcium/calmodulin-dependent protein kinase kinase 2(CaMKK2)-AMPK signaling pathway based on existing researches. L02 cells were induced by 100 mmol·L~(-1) ethanol for 48 h to establish the model of ALD in vitro, and 100, 50, and 25 μmol·L~(-1) concentration of MFA was treated. MiR-378b plasmids(containing the overexpression plasmid-miR-378b mimics, silence plasmid-miR-378b inhibitor, and their respective negative control-miR-378b NCs) were transfected into L02 cells by electroporation to up-regulate or down-regulate the levels of miR-378b in L02 cells. The levels of total cholesterol(TC) and triglyceride(TG) in cells were detected by commercial diagnostic kits and automatic biochemical analyzers. The expression levels of miR-378b in L02 cells were detected by real-time quantitative polymerase chain reaction(qRT-PCR). CaMKK2 mRNA levels were detected by PCR, and protein expressions of related factors involved in lipid synthesis, decomposition, and transport in lipid metabolism were detected by Western blot. The results displayed that ethanol significantly increased TG and TC levels in L02 cells, while MFA decreased TG and TC levels. Ethanol up-regulated the miR-378b level, while MFA effectively inhibited the miR-378b level. The overexpression of miR-378b led to lipid accumulation in ethanol-induced L02 cells, while the silence of miR-378b improved the lipid deposition induced by ethanol. MFA activated the CaMKK2-AMPK signaling pathway by lowering miR-378b, thus improving lipid synthesis, decomposition, and transport, which improved lipid deposition in L02 cells. This study shows that MFA improves lipid deposition in L02 cells by regulating the CaMKK2-AMPK pathway through miR-378b.
Humans ; Ethanol/toxicity* ; AMP-Activated Protein Kinases/metabolism* ; Fatty Liver ; Triglycerides ; MicroRNAs/genetics* ; Calcium-Calmodulin-Dependent Protein Kinase Kinase/genetics*

Adult ; Calmodulin-Binding Proteins ; metabolism ; Desmin ; metabolism ; Diagnosis, Differential ; Female ; Humans ; Leiomyoma ; metabolism ; pathology ; surgery ; Leiomyosarcoma ; pathology ; Spinal Canal ; Spinal Neoplasms ; metabolism ; pathology ; surgery ; Young Adult