成肌调节因子MyoD和myogenin在不同月龄DMD模型鼠mdx小鼠的表达

目的探讨成肌调节因子MyoD和myogenin在不同月龄DMD模型鼠mdx鼠的表达情况。方法取不同月龄DMD模型鼠mdx鼠以及相应的同龄正常C57鼠的腓肠肌,冰冻切片后用HE染色显示肌肉病理,SABC-DAB染色检测成肌调节因子MyoD和myogenin的表达。结果不同月龄mdx鼠肌肉坏死和再生程度不同,MyoD和myogenin在1月龄mdx鼠表达最强,在13月龄mdx鼠仍有表达,在正常同龄C57鼠不表达。结论MyoD与Myogenin在肌肉损伤后的再生修复过程中起作用,可作为鉴定肌肉前体细胞和反映肌肉再生的指标。     

miR-222在大鼠骨骼肌损伤再修复中的表达

为分析miR-222在骨骼肌损伤修复中的表达水平,本研究选取跑台诱导骨骼肌损伤模型,参照Armstrong的实验动物模型,选取2月龄健康雄性SD大鼠,建立股直肌损伤模型,在下坡跑运动结束后的不同时刻取材,对血清CK水平进行检测,对股直肌冰冻切片(HE染色;横切)进行组织形态学分析,采用RT-PCR试验对miR-222水平进行检测。血清CK在股直肌运动后损伤过程中的表达水平持续增高;HE染色发现:安静对照组显示肌纤维排列紧密规律,大小均匀,呈多边形;与对照组相比,运动后不同时刻取材的组织切片染色显示肌纤维之间间隙变大,形状不规律,呈肿胀状态;miR-222在运动后表达较对照组整体上调。一次性长时间下坡跑运动可导致大鼠股直肌损伤,损伤后2周肌纤维细胞结构基本恢复正常,通过血清CK的变化特点,血清CK可作为运动性骨骼肌损伤评价的敏感指标之一。一次性下坡跑诱导的运动性骨骼肌损伤中miR-222表达上调,促进了骨骼肌损伤的修复。     

蛋白和抗氧化剂对离心运动后肌肉功能和疼痛的影响

大量研究证实补充蛋白质或抗氧化剂均可有效提高机体的运动能力,然而,蛋白质和抗氧化剂联用的效果尚不清楚。本研究将60只SD大鼠随机分为4组,安静组(CG)、运动组(EG)、蛋白组(PG)和蛋白+抗氧化剂组(PAG),每组15只。PG组大鼠按照0.5 g/kg的剂量灌胃乳清蛋白溶液,PAG组大鼠按照0.5 g/kg的剂量灌胃乳清蛋白和抗氧化剂(富含花青素的浆果提取物)溶液。CG和EG组大鼠灌胃等体积的蒸馏水,共灌胃1周。然后,EG、PG和PAG组大鼠进行90 min的离心运动。采用机械缩足阈值来反映各组大鼠离心运动后的肌肉酸痛程度,研究显示,离心运动48 h后,PG组和PAG组大鼠的机械缩足阈值明显高于EG组,并且PG组和PAG组高于PG组。多项研究均显示,IL-6、IL-1β、MG53和MyoD参与肌肉的损伤及修复过程。本研究检测了上述因子的变化情况,发现大鼠在离心运动48 h后,后胫骨前肌组织中IL-6、IL-1β、MG53和MyoD的蛋白表达水平均显著升高,而蛋白+抗氧化剂可显著抑制上述指标的升高。苏木精伊红(HE)染色显示,离心运动48 h后,运动组大鼠的肌纤维受损程度达39.43%,显著高于蛋白组(23.54%)和蛋白+抗氧化剂组(8.42%)。此外,蛋白和抗氧化剂可显著抑制离心运动诱导的血清肌酸激酶的升高,并提高超氧化物歧化酶的活性。本研究证实蛋白联合抗氧化剂可有效减少离心运动引起的肌肉损伤、抑制机体的炎症反应并降低肌肉酸痛程度。     

大负荷运动诱导大鼠骨骼肌损伤对其自噬超微结构及Beclin1和LC3-Ⅱ/Ⅰ的影响

目的:观察大负荷离心运动对大鼠骨骼肌自噬超微结构及自噬相关蛋白Beclin1和LC3Ⅱ/Ⅰ的影响。方法:48只SD雄性大鼠适应性训练后随机分成对照组(C,n=8)和大负荷离心运动组(E,n=40)。E组于跑台进行90 min下坡跑,运动后0 h、12 h、24 h、48 h和72 h取比目鱼肌,透射电镜观察其自噬体超微结构变化; Western blot检测Beclin1和LC3Ⅱ/Ⅰ蛋白表达;免疫荧光观测LC3的定位及含量变化。结果:E组比目鱼肌自噬体数量在运动后0 h、12 h和24 h均有增加,并伴LC3自噬荧光明显增强(P0.01),同时运动后48 h自噬荧光仍有显著性升高(P0.05); Beclin1和LC3Ⅱ/Ⅰ在大负荷离心干预后表达升高(P0.05),运动后12 h～24 h达到峰值(P0.01),直至运动后72 h完全恢复。结论:大负荷离心运动可诱导骨骼肌自噬超微结构变化,自噬蛋白表达增强,以上可能是运动损伤的骨骼肌功能下降的原因之一。     

离心运动对大鼠骨骼肌细胞凋亡和增殖的影响

目的:探讨离心运动对骨骼肌细胞凋亡和增殖的时序性影响。方法:50只8周龄SD大鼠随机分为对照组(C)和运动组(B1,B2,B3,B4)(n=10),运动组进行重复3 d的力竭性离心运动,TUNNEL法检测大鼠肱三头肌内侧头不同恢复时相细胞凋亡情况和免疫组化检测其细胞增殖核抗原(PCNA)的表达。结果:①骨骼肌细胞凋亡出现时序性变化,并与运动性骨骼肌微损伤出现了一致性,运动组凋亡指数明显高于对照组(P<0.05),运动后即刻凋亡指数升高,运动后24 h达到峰值,运动后48 h凋亡指数有所下降。②骨骼肌细胞增殖出现时序性,运动组增殖指数明显高于对照组(P<0.05),运动后即刻增殖指数较高,运动后3 h增殖指数有所下降,运动后24 h增殖指数达到峰值,到运动后48 h下降,但还未恢复到对照组。并与细胞凋亡呈中度相关(P<0.05)。结论:①细胞凋亡是诱发骨骼肌再发性损伤的一个因素。②细胞凋亡可能是骨骼肌细胞再生的一个启动因素。     

大负荷运动诱导大鼠骨骼肌损伤对其自噬超微结构及Beclin1和LC3-II/I的影响*

目的: 观察大负荷离心运动对大鼠骨骼肌自噬超微结构及自噬相关蛋白Beclin1和LC3II/I的影响。方法: 48只SD雄性大鼠适应性训练后随机分成对照组(C,n=8)和大负荷离心运动组(E,n=40)。E组于跑台进行90 min下坡跑,运动后0 h、12 h、24 h、48 h和72 h取比目鱼肌,透射电镜观察其自噬体超微结构变化;Western blot检测Beclin1和LC3II/I蛋白表达;免疫荧光观测LC3的定位及含量变化。结果: E组比目鱼肌自噬体数量在运动后0 h、12 h和24 h均有增加,并伴LC3自噬荧光明显增强(P＜0.01),同时运动后48 h自噬荧光仍有显著性升高(P＜0.05);Beclin1和LC3II/I在大负荷离心干预后表达升高(P＜0.05),运动后12 h～24 h达到峰值(P＜0.01),直至运动后72 h完全恢复。结论: 大负荷离心运动可诱导骨骼肌自噬超微结构变化,自噬蛋白表达增强,以上可能是运动损伤的骨骼肌功能下降的原因之一。     

穿戴腿部压缩套未能缓解下坡跑肌肉损伤和臂踝脉搏波速度

为了探讨下坡跑运动时穿戴腿部压缩套对运动后诱发肌肉损伤及动脉硬化指标-臂踝脉搏波速(brachial-ankle pulse wave velocity, baPWV)的影响,本研究选择12名无规律运动习惯的男性大学生,采用随机方式于运动中单腿穿戴腿部压缩套(实验腿),以另一腿为对照腿,接受一次70%保留心率(70%HRR)强度,坡度为-10°30 min原跑步机下坡跑运动,并于下坡跑运动前(前测)及下坡跑运动后24 h (后测)分别进行因变量的检测,检测项目包含肌酸激酶、baPWV、酸痛指数、主动关节活动度、肌肉肿胀围、最大自主等长收缩肌力及超声波股直肌肌肉厚度。本研究表明:下坡跑运动后24 h的CK值((467.08±229.64) U/L)显著高于前测((240.92±189.67) U/L)(p0.05);baPWV在实验处理及时间因子的交互作用未达显著,仅时间因子显示后测的baPWV ((1 110.71±51.30) cm/s)显著高于前测((1 042.92±38.17) cm/s)(p0.05);酸痛指数、主动关节活动度、肌肉肿胀围、最大自主等长收缩肌力及超声波股直肌肌肉厚度等在实验处理及时间因子亦无交互作用,且实验处理主要效果亦无显著性(p0.05)。本研究初步得出结论,穿戴腿部压缩套并无法减缓下坡跑运动所引起的肌肉损伤,及随后的延迟性肌肉酸痛与暂时性的baPWV上升现象。     

甘油诱导的骨骼肌损伤修复过程肌间脂形态学及肌分泌因子表达变化

研究发现在甘油诱导的小鼠肌肉损伤修复过程中可能存在肌间脂的沉积,而肌肉分泌因子（myokines）作为特殊的蛋白参与了肌肉与脂肪的多种生理过程.为研究肌肉内注射甘油后对肌间脂生成的影响,以及注射后肌肉分泌因子在肌肉损伤后修复及肌间脂沉积过程中的表达趋势,本文选用三月龄C57BL/6品系小鼠,右腿胫骨前肌注射50% HBSS(V/V）甘油,左腿胫骨前肌注射等量的HBSS缓冲液作为对照.取注射后不同时期小鼠的胫骨前肌,冰冻切片技术检测肌肉再生及肌间脂沉积状况,实时定量PCR检测各分泌因子（IL-6、IL-15、MSTN、FNDC5、FGF21、myonectin和Insl6）的mRNA表达变化,酶联免疫分析（ELISA）检测分泌因子的蛋白表达变化.结果表明,在甘油诱导的肌肉损伤再生修复过程中存在肌间脂的生成,同时IL-6、Insl6、FGF21和IL-15的mRNA相对表达量在肌肉损伤修复过程中的前、中期变化明显,而MSTN和myonectin的mRNA相对表达量则在中、后期变化明显. IL-6、Insl6的蛋白表达量在前、中期明显升高.综上所述,甘油注射可引起肌肉损伤修复,并在这一过程中伴随着肌间脂的沉积,而肌肉分泌因子作为肌肉与脂肪之间的信息交换因子可能参与了肌肉损伤后的再生修复以及肌间脂的形成.     

AMPK α及p-AMPK α在运动过程中不同纤维类型骨骼肌中的表达变化

目的:检测腺苷酸活化蛋白激酶α(AMPKα)及磷酸化腺苷酸活化蛋白激酶α(p-AMPKα)在运动过程中不同纤维类型骨骼肌中的表达变化。方法:雄性C57BL/6小鼠随机分为对照组(运动前)、运功中(运动1 h后)和耗竭组(n=6)。放入跑台以15m/min的速度分别在运动前、运动1 h后及运动耗竭后取各组小鼠腓肠肌、比目鱼肌和跖肌。利用Western blot检测AMPKα及p-AMPKα的表达变化。结果:p-AMPKα在运动中及耗竭组腓肠肌、比目鱼肌和跖肌中持续高表达,尤其以比目鱼肌中表达变化最为显著。结论:p-AMPKα在运动过程中骨骼肌中的表达与肌纤维类型有关。     

补糖和/或刺五加对大鼠运动后骨骼肌细胞AMPK蛋白表达的影响

目的:研究补糖和刺五加对大鼠运动后骨骼肌细胞的AMP激活蛋白激酶(AMPK)蛋白表达的影响及其恢复期的时相性变化。方法:128只SD大鼠大鼠随机分为训练对照组(C组)、训练补糖组(G组)、训练补刺五加皂甙组(A组)和训练补糖补刺五加皂甙组(GA组)四大组,补糖和刺五加均在运动后0.5 h内灌胃给予。根据运动前和运动后不同时间(0 h,4 h,12 h)采样,共分为16小组(n=8)。采用Western blot方法分析骨骼肌的AMPK蛋白含量。结果:①运动后骨骼肌的AMPK蛋白表达量上调,运动后即刻最高(209.23±21.32),随后逐渐恢复;②补药显著地提高了机体在消耗糖原运动后即刻和4 h后的股四头肌AMPK蛋白含量(225.11±20.58和186.31±15.26vs195.19±13.31和157.11±16.43),运动后12 h两组间没有差异;③补糖对骨骼肌AMPK的蛋白表达量的影响没有统计学意义;④补糖同时补药可提高运动后即刻和4 h后的股四头肌AMPK蛋白含量(217.96±19.25和191.86±14.69),但是运动后12h反而低于对照组(121.89±15.23vs137.92±16.01)。结论:运动可激活骨骼肌细胞AMPK,补充刺五加皂甙可上调运动后的AMPK蛋白表达,补糖则没有影响。     

失血性休克大鼠淋巴管及血管压力对去甲肾上腺素反应的相关性研究

目的:观察失血性休克(HS)大鼠淋巴管与血管对去甲肾上腺素(NE)反应性的变化,探讨淋巴管与血管反应性的关系。方法:大鼠行左侧腹部手术,分离胸导管,测量淋巴管压力(LP);股部手术,经股动脉测量平均动脉血压(MAP)。休克组经股动脉放血复制HS模型(维持MAP40mmHg左右,3h),假手术(sham)组仅手术。在休克不同时间点(或相当),股静脉注射NE(5μg/kg.bw),观察给予NE前后两组大鼠LP以及MAP的变化。结果:休克即刻淋巴管对NE的反应性与sham组无明显差异,到休克0.5h时淋巴管对NE的升压反应开始减弱,至休克3h依然维持低反应性;与sham组相比,休克组血管对NE反应性呈双相表现,休克即刻血管高反应性,休克1h后对NE的升压作用开始减弱,表现为血管低反应性;休克后二者的反应性相关。结论:大鼠HS后淋巴管出现低反应性,且出现在血管低反应性之前;休克发展进程中淋巴管与血管对NE的低反应性呈正相关。     

Role of chaperone-mediated autophagy in degrading Huntington＇s disease-associated huntingtin protein

Mutant N-terminal huntingtin （Htt） protein resulting from Huntington＇s disease （HD） with expanded polyglutamine accumulates and forms aggregates in vulnerable neurons. Both ubiquitin proteasomai and autophagic pathways con- tribute to the degradation of mutant Htt. Here, we focus on the involvement of chaperone-mediated autophagy （CMA）, a selective form of autophagy in the clearance of Htt. Selective catabolism in CMA is conferred by the presence of a KFERQ-Iike targeting motif in the substrates, by which molecular chaperones recognize the hydrophobic surfaces of the misfolded substrates, and transfer them to the lysosomal membrane protein type-2A, LAMP-2A. The substrates are taken into the lysosomes through LAMP-2A and are rapidly degraded by the lysosomal enzymes. Taken together, we summarize the recent evidence to elucidate that Htt is also a potential substrate of CMA. We propose that the manipulation of CMA could be a therapeutic strat- egy for HD.     

Intracellular and Extracellular Phosphatidylinositol 3-Phosphate Produced by Phytophthora Species Is Important for Infection

RxLR effectors produced by Phytophthora pathogens have been proposed to bind to phosphatidylinositol 3-phosphate （Ptdlns（3）P） to mediate their translocation into host cells and/or to increase their stability in planta. Since the levels of Ptdlns（3）P in plants are low, we examined whether Phytophthora species may produce Ptdlns（3）P to pro- mote infection. We observed that Ptdlns（3）P-specific GFP biosensors could bind to P. parasitica and P. sojae hyphae dur- ing infection of Nicotiana benthamiana leaves transiently secreting the biosensors, suggesting that the hyphae exposed Ptdlns（3）P on their plasma membrane and/or secreted Ptdlns（3）R Silencing of the phosphatidylinositol 3-kinases （PI3K） genes, treatment with LY294002, or expression of Ptdlns（3）pobinding proteins by P. sojae reduced the virulence of the pathogen on soybean, indicating that pathogen-synthesized Ptdlns（3）P was required for full virulence. Secretion of Ptdlns（3）P-binding proteins or of a PI3P-5-kinase by N. benthamiana leaves significantly increased the level of resist- ance to infection by P. parasitica and P. capsici. Together, our results support the hypothesis that Phytophthora species produce external Ptdlns（3）P to aid in infection, such as to promote entry of RxLR effectors into host cells. Our results derived from P. sojae RxLR effector Avrlb confirm that both the N-terminus and the C-terminus of this effector can bind Ptdlns（3）P.     

Retromer Subunits VPS35A and VPS29 Mediate Prevacuolar Compartment （PVC） Function in Arabidopsis

Intracellular protein routing is mediated by vesicular transport which is tightly regulated in eukaryotes. The protein and lipid homeostasis depends on coordinated delivery of de novo synthesized or recycled cargoes to the plasma membrane by exocytosis and their subsequent removal by rerouting them for recycling or degradation. Here, we report the characterization of protein affected trafficking 3 （pat3） mutant that we identified by an epifluorescence-based for- ward genetic screen for mutants defective in subcellular distribution of Arabidopsis auxin transporter PIN1-GFR While pat3 displays largely normal plant morphology and development in nutrient-rich conditions, it shows strong ectopic intracellular accumulations of different plasma membrane cargoes in structures that resemble prevacuolar compart- ments （PVC） with an aberrant morphology. Genetic mapping revealed that pat3 is defective in vacuolar protein sorting 35A （VPS35A）, a putative subunit of the retromer complex that mediates retrograde trafficking between the PVC and trans-Golgi network. Similarly, a mutant defective in another retromer subunit, vps29, shows comparable subcellular defects in PVC morphology and protein accumulation. Thus, our data provide evidence that the retromer components VPS35A and VPS29 are essential for normal PVC morphology and normal trafficking of plasma membrane proteins in plants. In addition, we show that, out of the three VPS35 retromer subunits present in Arabidopsis thaliana genome, the VPS35 homolog A plays a prevailing role in trafficking to the lyric vacuole, presenting another level of complexity in the retromer-dependent vacuolar sorting.     

ARMS法检测非小细胞肺癌表皮生长因子受体基因突变及临床意义

目的：探讨应用突变特异性扩增系统法（ARMS）检测非小细胞肺癌（NSCLC）表皮生长因子受体（EGFR）基因突变的特点。方法：收集220例浙江南部地区NSCLC患者肿瘤样本,分别采用ARMS法和测序法检测EGFR基因18、19、20、21号外显子突变情况,并分析EGFR突变与病理类型、突变种类、患者年龄和性别的关系。结果：两方法比较,相符率为86．81％（158/182,Kappa=0．732,P〈0．01）。总突变率为47．27％（104/220）,其中腺癌的突变率明显高于鳞癌（52．46％zJs17．14％;P〈0．01）。肺腺癌中,女性患者EGFR突变率明显高于男性（65．56％∞39．78％;P〈0．01）。突变样本中,21外显子错义突变（L858R）所占比例最高（62．5％,65/104）,19外显子缺失（19Del）其次（43．27％,45/104）,其中两者同时突变占5．77％（6/104）;但腺癌女性与男性患者L858R突变率（64．41％∞56．76％）不存在显著性差别。结论：采用ARMS法检测EGFR基因突变较测序法敏感,突变主要发生在女性肺腺癌患者,以L858R突变为主。     

Prostaglandin E2 modulates F-actin stress fiber in FSS-stimulated MC3T3-E1 cells in a PKA-dependent manner

The effect of prostaglandin E2（PGE2） on bone mass has been well-established in vivo. Previous studies have showed that PGE2 increases differentiation, proliferation, and regu- lates cell morphology through F-actin stress fiber in statically cultured osteoblasts. However, the effect of PGE2 on osteo- blasts in the presence of fluid shear stress （FSS）, which could better uncover the anabolic effect of PGEz in vivo, has yet to be examined. Here, we hypothesized that PGE2 modulates F-actin stress fiber in FSS-stimulated MC3T3-E1 osteoblastic cells through protein kinase A （PKA） pathway. Furthermore, this PGE2-induced F-actin remodeling was associated with the recovery of cellular mechanosensitivity. Our data showed that treatment with 10 nM dmPGE2 for 15 rain significantly suppressed the F-actin stress fiber intensity in FSS-stimulated cells in a PKA-dependent manner. In addition, dmPGE2 treatment enhanced the cells＇ calcium peak magnitude and the percentage of responding cells in the second FSS stimulation, though these effects were abolished and attenuated by co-treatment with phalloidin. Our results demonstrated that 10 nM dmPGE2 was able to accelerate the ＇reset＇ process of F-actin stress fiber to its pre-stimulated level partially through PKA pathway, and thus promoted the recovery of cellular mechanosensitivity. Our finding provided a novel cellular mechanism by which PGE2 increased bone forma- tion as shown in vivo, suggesting that PGE2 could be a potential target for treatments of bone formation-related diseases.     

Thermal comfort and thermoregulation in manned space flight

Exposure to thermal environment is one of the main concerns for manned space exploration. By focusing on the works performed on thermoregulation at microgravity or simulated microgravity, we endeavored to review the investigation on space thermal environmental physiology. First of all, the application of medical requirements for the crew module design from normal thermal comfort to accidental thermal emergencies in a space craft will be addressed. Then, alterations in the autonomic and behavioral temperature regulation caused by the effect of weightlessness both in space flight and its simulation on the ground are also discussed. Furthermore, countermeasures like exercise training, simulated natural ventilation, encouraged drink, etc., in the protection of thermoregulation during space flight is presented. Finally, the challenge of space thermal environment physiology faced in the future is figured out.     

A High-Density SNP Genotyping Array for Rice Biology and Molecular Breeding

A high-density single nucleotide polymorphism （SNP） array is critically important for geneticists and molecu- lar breeders. With the accumulation of huge amounts of genomic re-sequencing data and available technologies for accurate SNP detection, it is possible to design high-density and high-quality rice SNP arrays. Here we report the devel- opment of a high-density rice SNP array and its utility. SNP probes were designed by screening more than 10 000 000 SNP loci extracted from the re-sequencing data of 801 rice varieties and an array named RiceSNP50 was produced on the Illumina Infinium platform. The array contained 51 478 evenly distributed markers, 68% of which were within genic regions. Several hundred rice plants with parent/F1 relationships were used to generate a high-quality cluster file for accurate SNP calling. Application tests showed that this array had high genotyping accuracy, and could be used for dif- ferent objectives. For example, a core collection of elite rice varieties was clustered with fine resolution. Genome-wide association studies （GWAS） analysis correctly identified a characterized QTL. Further, this array was successfully used for variety verification and trait introgression. As an accurate high-throughput genotyping tool, RiceSNP50 will play an important role in both functional genomics studies and molecular breeding.     

An XA21-Associated Kinase （OsSERK2） Regulates Immunity Mediated by the XA21 and XA3 Immune Receptors

The rice XA21 immune receptor kinase and the structurally related XA3 receptor confer immunity to Xanthomonas oryzae pv. oryzae （Xoo）, the causal agent of bacterial leaf blight. Here we report the isolation of OsSERK2 （rice somatic embryogenesis receptor kinase 2） and demonstrate that OsSERK2 positively regulates immunity mediated by XA21 and XA3 as well as the rice immune receptor FLS2 （OsFLS2）. Rice plants silenced for OsSerk2 display altered morphology and reduced sensitivity to the hormone brassinolide. OsSERK2 interacts with the intracellular domains of each immune receptor in the yeast two-hybrid system in a kinase activity-dependent manner. OsSERK2 undergoes bidi- rectional transphosphorylation with XA21 in vitro and forms a constitutive complex with XA21 in vivo. These results demonstrate an essential role for OsSERK2 in the function of three rice immune receptors and suggest that direct interaction with the rice immune receptors is critical for their function. Taken together, our findings suggest that the mechanism of OsSERK2-meditated regulation of rice XA21, XA3, and FLS2 differs from that of AtSERK3/BAK1-mediated regulation of Arabidopsis FLS2 and EFR.     

Phosphatidic Acid （PA） PP2A Activity and PIN1 Binds PP2AA1 to Regulate Polar Localization

Phospholipase D （PLD） exerts broad biological functions in eukaryotes through regulating downstream effectors by its product, phosphatidic acid （PA）. Protein kinases and phosphatases, such as mammalian target of rapa- mycin （mTOR）, Protein Phosphatase 1 （PP1） and Protein Phosphatase 2C （PP2C）, are PA-binding proteins that execute crucial regulatory functions in both animals and plants. PA participates in many signaling pathways by modulating the enzymatic activity and/or subcellular localization of bound proteins. In this study, we demonstrated that PLD-derived PA interacts with the scaffolding A1 subunit of Protein Phosphatase 2A （PP2A） and regulates PP2A-mediated PIN1 dephos- phorylation in Arabidopsis. Genetic and pharmacological studies showed that both PA and PP2A participate in the regu- lation of auxin distribution. In addition, both the phosphorylation status and polar localization of PIN1 protein were affected by PLD inhibitors, Exogenous PA triggered the membrane accumulation of PP2AA1 and enhanced the PP2A activity at membrane, while PLD inhibition resulted in the reduced endosomal localization and perinuclear aggregation of PP2AA1. These results demonstrate the important role of PLD-derived PA in normal PP2A-mediated PIN dephosphoryl- ation and reveal a novel mechanism, in which PA recruits PP2AA1 to the membrane system and regulates PP2A function on membrane-targeted proteins. As PA and PP2A are conserved among eukaryotes, other organisms might use similar mechanisms to mediate multiple biological processes.