基于p38MAPK/SERCA2α通路观察羟基红花黄色素A对大鼠心肌缺血/再灌注损伤的保护作用

目的:基于p38丝裂原活化蛋白激酶/肌质网Ca^(2+)-ATP酶2α(p38MAPK/SERCA2α)通路观察羟基红花黄色素A(HSYA)对大鼠心肌缺血/再灌注损伤(MIRI)的保护作用。方法:120只SD雄性大鼠随机分为假手术组(Sham组)、缺血再灌注组(I/R组)、HSYA 5 mg/kg组、HSYA 10 mg/kg组、HSYA 20 mg/kg组及p38MAPK信号通路抑制剂组(SB203580组)。5、10、20 mg/kg HSYA组大鼠分别灌胃给予对应剂量HSYA,SB203580组给予100µg/kg SB203580,末次灌胃结束后制作MIRI模型,Sham组仅切开左胸暴露心脏不结扎。缺氧4 h、复氧12 h建立H9C2心肌细胞OGD/R损伤模型并分为6组:对照组(Control组)、缺氧复氧模型组(OGD/R组)、5、10、20µmol/L HSYA组及SB203580组,Control组、OGD/R组不进行药物干预。TTC染色测定大鼠心肌梗死面积;超声心动图检测大鼠心脏功能;HE染色观察大鼠心肌组织病理学改变;Annexin V-FITC/PI双染法检测大鼠心肌组织和H9C2细胞凋亡;检测大鼠血清氧化应激及心肌酶指标;ELISA检测大鼠心肌组织和H9C2细胞炎症因子含量;CCK8及EdU染色检测H9C2细胞增殖能力;qRT-PCR检测心肌组织和H9C2细胞p38MAPK、SERCA2αmRNA表达;Western blot检测大鼠心肌组织和H9C2细胞p38MAPK、p-p38MAPK、SERCA2α、B细胞淋巴瘤-2(Bcl-2)、Bcl-2相关X蛋白(Bax)的蛋白表达。结果:10µmol/L或10 mg/kg HSYA能够提高左室射血分数(LVEF)、左室短轴缩短率(LVFS)、Bcl-2、SERCA2α水平,降低肌酸激酶(CK)、乳酸脱氢酶(LDH)、天冬氨酸转氨酶(AST)、超氧化物歧化酶(SOD)活力,降低Bax、肌钙蛋白Ⅰ(cTnⅠ)、丙二醛(MDA)、TNF-α、IL-1β、IL-6、p-p38MAPK/p38MAPK水平,促进心肌细胞增殖,抑制细胞凋亡,减少心肌梗死面积,改善心肌损伤。结论:HSYA能够抑制心肌细胞凋亡、氧化应激及炎症,从而减轻MIRI,其机制可能与p38MAPK/SERCA2α信号通路有关。

Ca2+/calmodulin-dependent protein kinase II regulates colon cancer proliferation and migration via ERK1/2 and p38 pathways

AIM To investigate the role of calmodulin-dependent protein kinase Ⅱ(Ca MKⅡ) in colon cancer growth,migration and invasion.METHODS Ca MKⅡ expression in colon cancer and paracancerous tissues was evaluated via immunochemistry. Transcriptional and posttranscriptional levels of Ca MKⅡin tissue samples and MMP2,MMP9 and TIMP-1 expression in the human colon cancer cell line HCT116 were assessed by q RTPCR and western blot. Cell proliferation was detected with the MTT assay. Cancer cell migration and invasion were investigated with the Transwell culture system and woundhealing assay.RESULTS We first demonstrated that CaMK Ⅱ was ove rexpressed in human colon cancers and was associated with cancer differentiation. In the human colon cancer cell line HCT116,the Ca MKII-specific inhibitor KN93,but not its inactive analogue KN92,decreased cancer cell proliferation. Furthermore,KN93 also significantly prohibited HCT116 cell migration and invasion. The specific inhibition of ERK1/2 or p38 decreased the proliferation and migration of colon cancer cells.CONCLUSION Our findings highlight Ca MKⅡ as a potential critical mediator in human colon tumor development and metastasis.

Combining Phytate/Ca^(2+) Fractionation with Trichloroacetic Acid/Acetone Precipitation Improved Separation of Low-Abundant Proteins of Wheat (Triticum aestivum L.) Leaf for Proteomic Analysis

Proteomic assessment of low-abundance leaf proteins is hindered by the large quantity of ribulose-1,5-bisphosphate carboxylase/oxygenase （Rubisco） present within plant leaf tissues. In the present study, total proteins were extracted from wheat （Triticum aestivum L.） leaves by a conventional trichloroacetic acid （TCA）/acetone method and a protocol first developed in this work. Phytate/Ca2＋ fractionation and TCA/acetone precipitation were combined to design an improved TCA/acetone method. The extracted proteins were analysed by two-dimensional gel electrophoresis （2-DE）. The resulting 2-DE images were compared to reveal major differences. The results showed that large quantities of Rubisco were deleted from wheat leaf proteins prepared by the improved method. As many as （758±4） protein spots were detected from 2-DE images of protein extracts obtained by the improved method, 130 more than those detected by the TCA/acetone method. Further analysis indicated that more protein spots could be detected at regions of pI 4.00-4.99 and 6.50-7.00 in the improved method-based 2-DE images. Our findings indicated that the improved method is an efficient protein preparation protocol for separating low-abundance proteins in wheat leaf tissues by 2-DE analysis. The proposed protocol is simple, fast, inexpensive and also applicable to protein preparations of other plants.

Role of Protein Kinase C in the Activation of Store-operated Ca^(2+) Entry in Airway Smooth Muscle Cells

Store-operated Ca2＋ channels （SOCs） are plasma membrane Ca2＋ permeable channels activated by depletion of intracellular Ca2＋ store. Ca2＋ entry through SOCs is known as store-operated Ca2＋ entry （SOCE）, which plays an important role in the functional regulation of airway smooth muscle cells （ASMCs）. Protein kinase C （PKC） has been shown to have an activating or inhibiting effect on SOCE, depending on cell types and PKC isoforms that are involved. In ASMCs, the effect of PKC on SOCE has not been elucidated so far. In this study, the role of PKC in the activation of SOCE in rat ASMCs was examined by using Ca2＋ fluorescence imaging technique. The results showed that acute application of PKC activators PMA and PDBu did not affect SOCE induced by the sarcoplasmic reticulum Ca2＋-ATPase （SERCA） inhibitor thapsigargin. The non-selective PKC inhibitor chelerythrine significantly inhibited thapsigargin- and bradykinin-induced SOCE. RT-PCR assay identified PKCα, δ and ε isoforms in rat ASMCs. PKCα-selective inhibitor G6976 and PKCε-inhibiting peptide Epsilon-V1-2 had no effect on SOCE; by contrast, PKCδ-selective inhibitor rottlerin attenuated SOCE dramatically, suggesting that PKCδ was the major PKC isoform involved in the activation of SOCE in ASMCs. Moreover, PKC down-regulation by extended exposure to high doses of PMA or PDBu also reduced SOCE, confirming the essential role of PKC in the activation of SOCE in ASMCs. In addition, PKC down-regulation did not influence the expression of stromal interaction molecule 1 （STIM1） and Orai1, two elementary molecules in the regulation and activation of SOCs. These results identified PKCδ as an essential PKC isoform involved in the activation of SOCE, and confirmed that PKC regulates the function of ASMCs in a SOCE-dependent manner.

诱导性低温复苏对失血性休克大鼠肠组织Ca^(2+)/钙调蛋白依赖性蛋白激酶Ⅰ表达影响

目的探讨诱导性低温复苏对失血性休克大鼠肠组织Ca^(2+)/钙调蛋白依赖性蛋白激酶Ⅰ(CaMKⅠ)表达的影响。方法选取成年雄性Wistar大鼠30只,随机分为假手术组(n=6)、常温复苏组(n=12)以及低温复苏组(n=12)。假手术组仅进行外科插管及相关手术操作,不建立失血性休克模型;常温复苏组及低温复苏组每只大鼠放血25 ml/kg,构建失血性休克模型,休克60 min后分别采取38℃和32℃复苏并维持60 min,复苏结束后将大鼠体温恢复至38℃并监测血流动力学3 h。大鼠复苏3 h后,3组均随机选取50%的大鼠处死,取小肠黏膜、肠系膜淋巴结及血液,剩余大鼠进行72 h生存分析。采用定量聚合酶链式反应(PCR)及蛋白质印迹法分别检测3组大鼠肠黏膜中CaMKⅠmRNA及蛋白表达情况,应用酶联免疫吸附试剂盒检测大鼠血清炎性因子表达情况,同时,进行细菌移位检测。结果复苏3 h后,低温复苏组大鼠的心率和平均动脉压(MAP)均低于常温复苏组,而心输出量、每搏量和射血分数均高于常温复苏组,差异有统计学意义(P<0.05)。设定72 h为观察终点,假手术组大鼠于观察终点时全部存活,低温复苏组大鼠的生存时间为(63.50±9.59)h,明显长于常温复苏组的(46.83±19.59)h,差异有统计学意义(P<0.05)。在液体复苏3 h后,低温复苏组CaMKⅠmRNA表达水平、灰度值均明显低于常温复苏组,差异有统计学意义(P<0.05);常温复苏组与低温复苏组CaMKⅠmRNA、蛋白表达水平均明显高于假手术组,差异有统计学意义(P<0.05)。假手术组大鼠血清中CaMKⅠ、肿瘤坏死因子α(TNF-α)、白细胞介素(IL)-1β、IL-6和IL-8水平明显低于常温复苏组和低温复苏组,IL-10水平高于常温复苏组,但低于低温复苏组,差异有统计学意义(P<0.05)。低温复苏组大鼠血清中CaMKⅠ、TNF-α、IL-1β、IL-6和IL-8水平明显低于常温复苏组,IL-10水平明显高于常温复苏组,差异有统计学意义(P<0.05)。复苏3 h后,低温复苏组大鼠血液细菌移位量、肠系膜淋巴结细菌移位量均明显低于常温复苏组,差异有统计学意义(P<0.05)。结论在诱导性低温复苏条件下,失血性休克大鼠肠组织中CaMKⅠmRNA及蛋白水平表达降低,大鼠生存时间延长,CaMKⅠ下调可能是诱导性低温复苏减轻大鼠失血性休克肠缺血再灌注损伤的重要分子机制。

转录因子HNF1A、HNF4A和FOXA2调节肝细胞蛋白质N-糖基化

Hepatocyte nuclear factor 1 alpha(HNF1A),hepatocyte nuclear factor 4 alpha(HNF4A),and forkhead box protein A2(FOXA2)are key transcription factors that regulate a complex gene network in the liver,cre-ating a regulatory transcriptional loop.The Encode and ChIP-Atlas databases identify the recognition sites of these transcription factors in many glycosyltransferase genes.Our in silico analysis of HNF1A,HNF4A.and FOXA2 binding to the ten candidate glyco-genes studied in this work confirms a significant enrich-ment of these transcription factors specifically in the liver.Our previous studies identified HNF1A as a master regulator of fucosylation,glycan branching,and galactosylation of plasma glycoproteins.Here,we aimed to functionally validate the role of the three transcription factors on downstream glyco-gene transcriptional expression and the possible effect on glycan phenotype.We used the state-of-the-art clus-tered regularly interspaced short palindromic repeats/dead Cas9(CRISPR/dCas9)molecular tool for the downregulation of the HNF1A,HNF4A,and FOXA2 genes in HepG2 cells-a human liver cancer cell line.The results show that the downregulation of all three genes individually and in pairs affects the transcrip-tional activity of many glyco-genes,although downregulation of glyco-genes was not always followed by an unambiguous change in the corresponding glycan structures.The effect is better seen as an overall change in the total HepG2 N-glycome,primarily due to the extension of biantennary glycans.We propose an alternative way to evaluate the N-glycome composition via estimating the overall complexity of the glycome by quantifying the number of monomers in each glycan structure.We also propose a model showing feedback loops with the mutual activation of HNF1A-FOXA2 and HNF4A-FOXA2 affecting glyco-genes and protein glycosylation in HepG2 cells.

Effects of β-TCP Ceramics on Intracellular Ca^(2+) Concentration,Mineralization of Osteoblast and Protein Structure

β-TCP, as one of calcium phosphates ceramics, exerts perfect biocompatibility and osteoconductivity, and is clinically used as a bone graft substitute for decades. Consequently, the effects of β-TCP ceramics on intracellular Ca2＋ concentration, mineralization of osteoblast and BSA protein structure were studied. Results showed that β-TCP could increase the intracelluar Ca2＋ concentration and mineralization of osteoblast, indicating that β-TCP ceramics could take part in the organic metabolism and the degradation product had no detrimental effect on osteoblast in vitro. Furthermore, β-TCP ceramics could increase the content of α-helix and β-pleated sheet and change BSA into more ordering structure, those changes might be favorable for the biomineralization after β-TCP ceramics implanted.

Amelioration of mitochondrial dysfunction in heart failure through S-sulfhydration of Ca^2＋/calmodulin-dependent protein kinase Ⅱ

OBJECTIVE To determine the functional role of hydrogen sulfide(H_2S) in protecting against mitochondrial dysfunction in heart failure through the inhibition of Ca^(2+)/calmodulin-dependent protein kinaseⅡ(Ca MKⅡ) using wild type and CSE knockout mouse models.METHODS Continuous subcutaneous injection isoprenaline(7.5 mg·kg^(-1) per day),once a day for 4 weeks to induce heart failure in male C57BL/6(6-8 weeks old) mice and CSE-/-mice.150 μmol·L^(-1) H_2O_2 was used to induce oxidative stress in H9c2 cells.Echocardiograph was used to detect cardiac parameters.H&E stain and Masson stain was to observation histopathological changes.Western blot was used to detect protein expression and activity.The si RNA was used to silence protein expression.HPLC was used to detect H_2S level.Biotin assay was used to detect the level of S-sulfhydration protein.RESULTS Treatment with S-propyl-L-cysteine(SPRC) or sodium hydrosulfide(Na HS),modulators of blood H_2S levels,attenuated the development of heart failure in animals,reduced lipid peroxidation,and preserved mitochondrial function.The inhibition Ca MKⅡ phosphorylation by SPRC and Na HS as demonstrated using both in vivo and in vitro models corresponded with the cardioprotective effects of these compounds.Interestingly,Ca MKⅡ activity was found to be elevated in CSE-/-mice as compared to wild type animals and the phosphorylation status of Ca MK Ⅱ appeared to relate to the severity of heart failure.Importantly,in wild type mice SPRC was found to promote S-sulfhydration of Ca MKⅡ leading to reduced activity of this protein however,in CSE-/-mice S-sulfhydration was abolished following SPRC treatment.CONCLUSION A novel mechanism depicting a role of S-sulfhydration in the regulation of Ca MKⅡ is presented.SPRC mediated S-sulfhydration of Ca MKⅡ was found to inhibit Ca MKⅡ activity and to preserve cardiovascular homeostasis.

非接触共培养体系下抑制ARPE-19中CAMKⅡ表达对HUVECs迁移和侵袭及管腔形成的影响

目的:探讨非接触共培养体系下抑制人视网膜色素上皮细胞(ARPE)中Ca2+/钙调蛋白依赖性蛋白激酶Ⅱ(CAMKⅡ)表达对人脐静脉内皮细胞(HUVECs)迁移、侵袭、管腔形成的影响。方法:将过表达CAMKⅡ-δ的ARPE-19样本进行RNA测序,应用生物信息学分析差异基因参与的功能。使用transwell小室构建ARPE-19和HUVECs非接触共培养体系,根据实验干预措施分为:空白组:仅接种未共培养的HUVECs,无ARPE-19细胞;对照组:ARPE-19和HUVECs细胞均使用完全培养基进行共培养;AIP组(CAMKⅡ抑制组):ARPE-19使用含有AIP(160 nmol/L)的完全培养基,HUVECs使用完全培养基,进行共培养。检测HUVECs迁移、侵袭和管腔形成能力的变化,并通过Western blotting检测CAMKⅡ/AMPK/mTOR/VEGFA蛋白表达水平。结果:生信分析发现差异基因参与细胞生长与死亡和细胞运动等生物学过程。划痕和transwell迁移实验均表明AIP组的HUVECs相对迁移率均明显低于对照组(均P<0.05)。而侵袭和小管形成实验表明,AIP组的相对侵袭率和相对管腔形成率较对照组无明显改变(均P>0.05)。Western blotting结果表明AIP组CAMKⅡ、P-mTOR、VEGFA蛋白表达较对照组均明显下调,而P-AMPK蛋白表达较明显上调(均P<0.05)。结论:在非接触共培养体系下抑制ARPE-19细胞中CAMKⅡ表达可以显著降低HUVECs迁移能力,但不能改变侵袭和管腔形成能力,这可能是通过AMPK/mTOR/VEGFA信号通路实现的。

石杉碱甲对血管性痴呆小鼠海马神经细胞[Ca^(2+)]_i及钙调蛋白、蛋白激酶Ⅱ信使核糖核酸表达的影响

目的 :观察石杉碱甲对血管性痴呆 (VD)小鼠海马神经细胞 [Ca2 + ] i 和钙调蛋白 (CaM) ,Ca2 +钙调蛋白依赖性蛋白激酶Ⅱ (CaMPKⅡ )mRNA表达的影响。方法 :采用双侧颈总动脉线结法 ,制作小鼠VD模型 ,并设假手术对照组 ,石杉碱甲为治疗组 ;术后d 2 9,30测试学习、记忆成绩。利用激光共焦显微镜检测各组海马神经细胞 [Ca2 + ] i;用RT PCR技术检测CaM ,CaMPKⅡmRNA。结果 :模型组[Ca2 + ] i 荧光强度 (44±s 3)显著高于假手术组(2 6± 4) (P <0 .0 1 )和石杉碱甲组 (2 8.5± 2 .5) (P<0 .0 1 ) ;模型组CaMmRNA含量 (0 .76± 0 .2 1 )显著低于假手术组 (1 .1 3± 0 .2 3) (P <0 .0 1 )和石杉碱甲组 (0 .97± 0 .1 9) (P <0 .0 5) ,CaMPKⅡmRNA含量(0 .43± 0 .0 7)显著低于假手术组 (0 .67± 0 .1 0 )(P <0 .0 1 )和石杉碱甲 (0 .61± 0 .0 8) (P <0 .0 1 )。结论 :石杉碱甲可降低VD小鼠海马神经细胞[Ca2 + ] i,提高CaM ,CaMPKⅡmRNA表达水平 。

有机磷农药对小白菜中可溶性蛋白质及SOD、Mg^(2+)-ATPase、Ca^(2+)-ATPase和CAT的影响

使用一定浓度甲胺磷农药喷洒小白菜后,测定7 d中其可溶性蛋白质及抗氧化酶(SOD、CAT、和蛋白酶M g2+-ATPase、C a2+-ATPase)的含量变化.结果表明,喷药后可溶性蛋白质在第2~4天含量比对照组减小,随后呈上升趋势;SOD和CAT在第2~6天均高于对照;而M g2+-ATPase、C a2+-ATPase第1~4天与对照相差不大,第5、6天略高于对照;第7天各物质都基本还原到与对照接近或持平.说明有机磷农药喷洒后致使植物体内产生了大量氧自由基,进而诱导细胞内防御活性氧自由基毒害的物质产生.

Ca^(2+)对水分胁迫下小麦诱导蛋白产生的影响

水分胁迫及ＡＢＡ处理可诱导丰抗８号小麦幼苗及其悬浮培养细胞中４４．２ＫＤ蛋白亚基的产生或大量合成。高浓度的Ｃａ２＋通道阻塞剂（Ｖｅｒａｐａｍｉｌ）处理丰抗８号小麦幼苗，可明显抑制水分胁迫诱导产生的４４．２ＫＤ蛋白亚基的大量合成，而悬浮培养细胞中，２０μＭ的异博定处理就可显著抑制由ＡＢＡ及ＡＢＡ＋ＰＥＧ所诱导的蛋白亚基含量的提高，说明Ｃａ２＋可能参与了干旱信号在胞内的传递过程；细胞对Ｃａ２＋通道阻塞剂的反应比幼苗更显著、更敏感。

铝对大鼠海马[Ca^(2+)]i和PKC生物活性影响

目的通过观察不同浓度慢性铝暴露对海马长时程增强(long-termpotentiation,LTP)的影响,检测海马细胞内Ca2+浓度和蛋白激酶C(PKC)生物活性,研究慢性铝暴露损伤学习记忆的机制。方法选择断乳后Wistar大鼠,以含有不同浓度AlCl3的蒸馏水进行饲养。3个月后,测定脑铝、血铝、海马细胞内Ca2+,测量记录大鼠海马LTP,用改良的Takai法测定PKC活性的变化。结果(1)各染铝组的[Ca2+]i与对照组比较,差异有统计学意义(P<0.01),但各染铝组间差异无统计学意义。(2)各染铝组PKC活性与对照组比较均降低,差异有统计学意义(P<0.01)。结论慢性铝暴露引起大鼠海马细胞内[Ca2+]i下降,使PKC活性降低,导致下游分子的活性受到影响,破坏LTP的形成,损害学习记忆功能。

血管性痴呆小鼠海马神经细胞静息态[Ca^(2+)]_i及CaMmRNA、CaMPKⅡmRNA表达的变化

目的 :观察血管性痴呆小鼠海马神经细胞内静息态游离Ca2 + 浓度 ([Ca2 + ]i)和钙调素 (CaM)、CaM依赖性蛋白激酶Ⅱ (CaMPKⅡ )mRNA表达水平的变化 ,探讨上述因素在血管性痴呆发病中的作用。方法 :采用双侧颈总动脉线结、缺血 /再灌注的方法 ,制备小鼠血管性痴呆模型 ,并设假手术组作为对照。分别于术后第 2 9d、第 30d进行学习、记忆成绩测试 ,然后快速取海马制备海马活细胞 ,以Fluo 3/AM为荧光探针 ,在激光扫描共聚焦显微镜下观察两组海马神经细胞静息态 [Ca2 + ]i 变化 ,并应用RT PCR技术检测海马神经细胞内CaMmRNA、CaMPKⅡmRNA的表达水平。结果 :①模型组的学习和记忆成绩均低于假手术组 (P <0 .0 5 ) ;②模型组神经细胞静息态 [Ca2 + ]i 显著高于假手术组 (P <0 .0 5 ) ;而CaMmRNA、CaMPKⅡmRNA表达水平低于假手术组 ,具有极其显著性差异 (P <0 .0 1)。结论 :海马神经细胞静息态 [Ca2 + ]i增高、CaMmRNA和CaMPKⅡmRNA表达减少是导致小鼠血管性痴呆发生的机制之一。

蛋白磷酸酶(PP1、PP2A)抑制剂Calyculin A对大鼠心脏血流动力学的影响

目的研究蛋白磷酸酶(PP1、PP2A)抑制剂Calyculin A对大鼠血流动力学的作用及其心肌细胞钙释放的特征。方法采用大鼠在体双压力(P-V loop)导管分析心脏血流动力学及主动脉压;采用场刺激的方法分析心肌细胞钙释放。结果左侧颈静脉给予Calyculin A(0. 8μg·kg-1)明显提高左心室收缩力,表现为明显增加左心室搏出功、心输出量、每搏输出量、射血分数、收缩末期压力-容积关系曲线斜率;明显改善心脏舒张功能,表现为明显降低左心室舒张末期压力-容积关系曲线斜率;增加主动脉收缩压、舒张压及脉压差; Calyculin A(100 nmol·L-1)明显增加心肌细胞钙释放的幅值及缩短钙回吸收拟合曲线的时间常数。结论 Calyculin A的正性肌力作用与肌浆网钙泵活性有关,蛋白磷酸酶(PP1、PP2A)可作为潜在靶点,用于开发正性肌力药物。

外源Ca^(2+)对茄子幼苗抗寒性的影响

以抗寒性不同的3个茄子品种为试材,研究了不同浓度的CaC l2(10,25,40 mmol/L)对其抗寒性的影响。结果表明,不同浓度的CaC l2处理后,各品种植物体内的SOD,POD,CAT活性升高、可溶性蛋白质含量增加;除荷苞长茄经40mmol/L的CaC l2处理的MDA含量增加外,其余浓度处理的各品种都降低。CaC l2对美国红茄的抗寒性影响最大。不同浓度对抗寒性的效果来看,10 mmol/L的CaC l2处理效果最好。

锌离子对大鼠海马突触体Ca^(2+)-Mg^(2+)ATP酶活性及蛋白合成的影响

行为实验己经证明，锌过多或缺锌均可影响脑功能。锌作为体内重要的微量元素，影响多种酶的活性及蛋白质和核酸的台成。本实验通过体外分离大鼠脑海马突触体，观察不同浓度锌离子对Ca2+－Mg2+ATP酶的活性和3H－Leu掺入突触蛋白合成的影响．结果表明：1．锌离子浓度在25μmol／L时增加该酶的活性（＜0．01），并促进3H－Leur掺入蛋白质的合成（＜0．05）。2．锌离子在50,100，200μmol／L的较高浓度时对Co2+－M2+ATP酶的活性有显著的抑制作用（分别为：P＜0.05．P＜0．01，P＜0.01），仅200μmol／L对3H—Leu掺入突触蛋白合成有抑制作用。本研究提示：适量的锌对突触体功能的维持是必要的，但剂量过高则起相反作用。

锌对大鼠成骨细胞膜Ca^(2+)-ATP酶活性的调节

为了研究锌对大鼠成骨细胞膜Ca2+ -ATP酶和Na+ 、K+ -ATP酶活性的影响及其机制,实验设对照组和3个补锌组。采用孔雀绿比色法同步测定膜Ca2+ -ATP酶和Na+ ,K+ -ATP酶活性,以研究Zn2+ 对酶活性的影响以及蛋白激酶C或钙调素特异性抑制剂对Zn2+ 诱导的成骨细胞膜Ca2+ -ATP酶活性的影响。结果表明,Zn2+ 可以显著提高成骨细胞膜Ca2+ -ATP酶活性,但对Na+ ,K+ -ATPase活性无影响;钙调素特异性抑制剂R24571对Zn2+ 诱导的Ca2+ -ATPase活性无影响,钙调素对膜Ca2+ -ATP酶基础活性也无激活作用;蛋白激酶C特异性抑制剂三氟拉嗪可使Zn2+ 诱导的Ca2+ -ATP酶的活性显著降低。因此,锌可能通过蛋白激酶C介导调节成骨细胞膜Ca2+

重组PICK1蛋白的多聚形式及其与Ca^(2+)和Mg^(2+)的结合

蛋白激酶Cα相互作用蛋白1(PICK1)是从线虫到人的所有生物中非常保守的一类存在于细胞质中的膜结合蛋白,在蛋白质转运,以及细胞内信号转导过程中发挥重要作用.通过基因重组技术获得PICK1及其截短的N-PDZ(1~110残基)和BAR-C(128~416残基)重组蛋白,结合变性与非变性聚丙烯酰胺凝胶电泳,以及分子排阻层析,表明溶液中的PICK1主要以二聚体形式存在.利用荧光光谱分析PICK1与金属离子Ca2+和Mg2+的结合情况.结果表明,在0.02 mol/L Hepes,pH 7.2,随着2种金属离子的不断滴加,PICK1在338 nm处的最大荧光强度逐渐降低,PICK1与Ca2+结合常数为Ka1=(2.34±0.20)×106L.mol-1,Ka2=(7.75±0.62)×105L.mol-1,而Mg2+结合常数为Ka=(5.00±0.40)×106L.mol-1.另外,对PICK1的N端区域N-PDZ和C端区域BAR-C的重组片段与金属离子Ca2+和Mg2+结合情况进一步分析表明,Ca2+既能与PICK1的N端N-PDZ结合,又可与C端BAR-C结合,而Mg2+只结合在PICK1的N-PDZ区域.比较Ca2+或Mg2+对PICK1结合脂质的影响,显示Ca2+能明显增强蛋白和脂质的结合.

大鼠脑缺血后P-CaMKⅡ的表达与Ca^(2+)浓度的关系

目的探讨脑缺血后脑组织Ca2+浓度和磷酸化钙调蛋白依赖性蛋白激酶Ⅱ(P-CaMKⅡ)表达的变化及其相关关系。方法采用大鼠大脑中动脉阻断模型,干湿质量法测量脑组织含水量,免疫组化方法检测P-CaMKⅡ的表达,Fura-2/AM荧光法测定水肿周围Ca2+浓度。结果与对照组相比,脑缺血后6 h,P-CaMKⅡ的表达、Ca2+浓度和脑含水量均开始上调,在脑缺血2~3 d表达最强;Ca2+浓度的变化与P-CaMKⅡ的表达强度呈正相关。结论脑缺血后由于细胞内Ca2+超载,导致CaMKⅡ磷酸化作用增强,它们可能共同参与了缺血性脑水肿的形成。