简介:Twomajorapoptosispathwayshavebeendefinedinmammaliancells,theFas/TNF-R1deathreceptorpathwayandthemitochondriapathway.TheBcl-2familyproteinsconsistofbothanti-apoptosisandpro-apoptosismembersthatregulateapoptosis,mainlybycontrollingthereleaseofcytochromecandothermitochondrialapoptoticevents.However,deathsignalsmediatedbyFas/TNF-R1receptorscanusuallyactivatecaspasesdirectly,bypassingtheneedformitochondriaandescapingtheregulationbyBcl-2familyproteins.Bidisanovelpro-apoptosisBcl-2familyproteinthatisactivatedbycaspase8inresponsetoFas/TNF-R1deathreceptorsignals.ActivatedBidistranslocatedtomitochondriaandinducescytochromecrelease,whichinturnactivatesdownstreamcaspases.Suchaconnectionbetweenthetwoapoptosispathwayscouldbeimportantforinductionofapoptosisincertaintypesofcellsandresponsibleforthepathogenesisofanumberofhumandiseases.
简介:小道,肿瘤坏死因素相关的导致apoptosisligand,是一个新奇有势力通过房间表面死亡受体Trail-R1和Trail-R2的激活的房间死亡小径的内长的使活跃之物。它的角色象在导致激活的房间死亡(AICD)的FasL一样,在免疫系统被表明了。然而,小道的机制导致了apoptosis遗体不清楚。在这份报告,重组体小道蛋白质被表示并且净化。导致apoptosis活动和JurkatT房间上的重组体小道的规定机制是探索试管内。Trypan蓝排除试金证明重组体小道蛋白质活跃地以一种剂量依赖者方式杀死了JurkatT房间。在JurkatT房间的导致小道的apoptosis被Bcl-2显著地在Bcl-2基因transfected房间在表示上减少。有PMA(phorbol12十四酸盐13醋酸盐)的处理,PKC使活跃之物,在JurkatT房间的压制的导致小道的apoptosis。由PMA的apoptosis的抑制被预告的处理与二度废除,一个PKC禁止者。总起来说,Bcl-2在表示上和PMA激活PKC,这被建议活跃地下面调整在JurkatT的调停小道的apoptosis房间。
简介:MYB蛋白质在真核细胞的有机体起重要作用。在植物,R1R2R3类型MYB蛋白质在房间周期控制工作。然而,R2R3类型MYB蛋白质是否也涉及房间部门过程,仍然保持未知。这里,我们报导那R2R3类型抄写因素基因,AtMYB59,涉及房间周期前进和根生长的规定。AtMYB59蛋白质在洋葱的原子核是局部性的表皮的房间并且transactivation活动。在酵母房间的AtMYB59的表示压制房间增长,和transformants与更长的房间有更多的原子核和更高的aneuploidDNA内容。在AtMYB59的保存领域的变化在酵母细胞生长上废除它的效果。在同步Arabidopsis房间暂停,AtMYB59基因明确地在房间周期前进期间在S阶段被表示。表示和promoter-GUS分析表明AtMYB59基因富有地在根被表示。转基因的植物overexpressingAtMYB59更短的根与野类型的植物(Arabidopsis就职Col-0)相比,并且在在根尖端的有丝分裂的房间的一半附近在中期。相反地,空变异的myb59-1比关口在中期让更长的根和更少有丝分裂的房间,建议那AtMYB59可以由扩大有丝分裂的房间的中期禁止根生长。AtMYB59调整许多下游的基因,包括CYCB1;1基因,可能通过到MYB应答的元素的绑定。这些结果在细胞周期规定和植物根生长为AtMYB59支持一个角色。
简介:新鲜的水息肉水螅属于门Cnidaria,它在bilaterians的外观前从后生动物的系分叉。以便在metazoans理解apoptosis的进化,我们开始阐明了在这个模型有机体的分子的细胞死亡机械。基于EST和整个水螅染色体集会,我们识别了15caspases。我们证明一个人在apoptosis期间被激活,四与N终端DED,卡片或DD领域有开始者caspases的特征,二在vitro经历autoprocessing。另外,我们描述七Bcl-2-like和二象Bak一样蛋白质。为大多数Bcl-2家庭蛋白质,我们观察了mitochondrial本地化。当在哺乳动物的房间表示了时,象HyBak一样1和2强烈导致的apoptosis。禁止的apoptosis与显示出特别强壮的保护的效果的HyBcl-2-like4在哺乳动物的房间由camptothecin劝诱了的六个Bcl-2家庭成员。这蛋白质也与象HyBak一样交往了1在酵母二混血儿的试金。在它的BH3领域的保存白氨酸的变化两个都与象HyBak一样废除了相互作用1并且anti-apoptotic效果。而且,我们BH-3-only描述新奇水螅蛋白质。这些之一与Bcl-2-like4交往了并且在哺乳动物的房间导致了apoptosis。我们的数据显示为房间死亡规定的一个复杂网络的进化在多细胞的组织的最早、最简单的水平产生了,它在此展出了一复杂性实质地高级比在protostome模型有机体Caenorhabditis和果蝇。
简介:Plasmamembrane(PM)Ca^2+-ATPaseactivityinpoplarapicalbudmeristematiccellsduringshort-day(SD)-induceddormancydevelopmentwasexaminedbyaceriumprecipitationEM-cytochemicalmethod.Ca^2+-ATPaseactivity,indicatedbythestatusofceriumphosphateprecipitatedgrains,waslocalizedmainlyontheinteriorface(cytoplasmicside)ofthePMwhenplantsweregrownunderlongdaysandreachedadeepdormancy.Afewreactionproductswerealsoobservedonthenuclearenvelope.Whenplantbudsweredevelopingdormancyafter28to42dofSDexposure,almostnoreactionproductswerepresentontheinteriorfaceofthePM.Incontrast,alargenumberofceriumphosphateprecipitatedgrainsweredistributedontheexteriorfaceofthePM.After70dofSDexposure,whenbudshaddevelopedadeepdormancy,thereactionproductsofCa^2+-ATPaseactivityagainappearedontheinteriorfaceofthePM.TheresultsseemedsuggestingthattwokindsofCa^2+-ATPasesmaybepresentonthePMduringtheSD-induceddormancyinpoplar.OneistheCa^2+-pumpingATPase,whichislocatedontheinteriorfaceofthePM,formaintainingandrestoringtheCa^2+homeostasis.Theothermightbeandecto-Ca^2+-ATPase,whichislocatedontheexteriorfaceofthePM,fortheexocytosisofcellwallmaterialsassuggestedbythefactofthecellwallthickeningduringthedormancydevelopmentinpoplar.
简介:OverexpressionandactivationofHER-2/neu(alsoknownasc-erbB-2),aproto-oncogene,wasfoundinabout30%ofhumanbreastcancers,promotingcancergrowthandmakingcancercellsresistanttochemo-andradio-therapy.Wild-typep53iscrucialinregulatingcellgrowthandapoptosisandisfoundtobemutatedordeletedin60-70%ofhumancancers.Andsomecancerswithawild-typep53donothavenormalp53function,suggestingthatitisimplicatedinacomplexprocessregulatedbymanyfactors.Inthepresentstudy,weshowedthattheoverexpressionofHER-2/neucoulddecreasetheamountofwild-typep53proteinviaactivatingPI3Kpathway,aswellasinducingMDM2nucleartranslocationinMCF7humanbreastcancercells.BlockageofPI3KpathwaywithitsspecificinhibitorLY294002causedG1-Sphasearrest,decreasedcellgrowthrateandincreasedchemo-andradio-therapeuticsensitivityinMCF7cellsexpressingwild-typep53.However,itdidnotincreasethesensitivitytoadriamycininMDA-MB-453breastcancercellscontainingmutantp53.OurstudyindicatesthatblockingPI3KpathwayactivationmediatedbyHER-2/neuoverexpressionmaybeusefulinthetreatmentofbreasttumorswithHER-2/neuoverexpressionandwild-typep53.