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991.
Li-qin Li Lun Liu Wei Zhuo Qian Chen Sheng Hu Shuang Peng Xi-yao Wang Yi-fei Lu Li-ming Lu 《Plant molecular biology》2018,96(3):265-278
Key message
KEG is involved in mediating the proteasome-dependent degradation of FDH, a stress-responsive enzyme. The UPS may function to suppress FDH mediated stress responses under favorable growth conditions.Abstract
Formate dehydrogenase (FDH) has been studied in bacteria and yeasts for the purpose of industrial application of NADH co-factor regeneration. In plants, FDH is regarded as a universal stress protein involved in responses to various abiotic and biotic stresses. Here we show that FDH abundance is regulated by the ubiquitin proteasome system (UPS). FDH is ubiquitinated in planta and degraded by the 26S proteasome. Interaction assays identified FDH as a potential substrate for the RING-type ubiquitin ligase Keep on Going (KEG). KEG is capable of attaching ubiquitin to FDH in in vitro assays and the turnover of FDH was increased when co-expressed with a functional KEG in planta, suggesting that KEG contributes to FDH degradation. Consistent with a role in regulating FDH abundance, transgenic plants overexpressing KEG were more sensitive to the inhibitory effects of formate. In addition, FDH is a phosphoprotein and dephosphorylation was found to increase the stability of FDH in degradation assays. Based on results from this and previous studies, we propose a model where KEG mediates the ubiquitination and subsequent degradation of phosphorylated FDH and, in response to unfavourable growth conditions, reduction in FDH phosphorylation levels may prohibit turnover allowing the stabilized FDH to facilitate stress responses.992.
Na+,K+/H+ antiporters regulate the pH of endoplasmic reticulum and auxin‐mediated development 下载免费PDF全文
Ligang Fan Lei Zhao Wei Hu Weina Li Ondřej Novák Miroslav Strnad Sibu Simon Jiří Friml Jinbo Shen Liwen Jiang Quan‐Sheng Qiu 《Plant, cell & environment》2018,41(4):850-864
AtNHX5 and AtNHX6 are endosomal Na+,K+/H+ antiporters that are critical for growth and development in Arabidopsis, but the mechanism behind their action remains unknown. Here, we report that AtNHX5 and AtNHX6, functioning as H+ leak, control auxin homeostasis and auxin‐mediated development. We found that nhx5 nhx6 exhibited growth variations of auxin‐related defects. We further showed that nhx5 nhx6 was affected in auxin homeostasis. Genetic analysis showed that AtNHX5 and AtNHX6 were required for the function of the endoplasmic reticulum (ER)‐localized auxin transporter PIN5. Although AtNHX5 and AtNHX6 were colocalized with PIN5 at ER, they did not interact directly. Instead, the conserved acidic residues in AtNHX5 and AtNHX6, which are essential for exchange activity, were required for PIN5 function. AtNHX5 and AtNHX6 regulated the pH in ER. Overall, AtNHX5 and AtNHX6 may regulate auxin transport across the ER via the pH gradient created by their transport activity. H+‐leak pathway provides a fine‐tuning mechanism that controls cellular auxin fluxes. 相似文献
993.
Objective
To synthesize and determine the antitumor activity of 10-chlorocanthin-6-one in ovarian cancer HO8910PM cells.Results
Among the synthesized canthin-6-one analogs, 10-chlorocanthin-6-one was the most cytotoxic (IC50 = 4.9 μM), as demonstrated by a dose-dependent cytotoxicity assay. Moreover, 10-chlorocanthin-6-one induced apoptosis through the activation of poly(ADP-ribose) polymerase and caspase-3 cleavage, upregulation of Bcl-2, and downregulation of Bim, x-linked inhibitor of apoptosis protein (XIAP), and survivin in HO8910PM cells. Furthermore, Bim RNA, upregulated in a concentration-dependent manner, and knockdown of Bim via short-hairpin RNAs attenuated the inhibitory effects of 10-chlorocanthin-6-one on HO8910PM cell growth.Conclusions
10-Chlorocanthin-6-one inhibits cell proliferation and induces apoptosis in H08910PM cells. The underlying molecular mechanisms of 10-chlorocanthin-6-one include activation of the Bim-mediated mitochondrial apoptotic pathway via upregulation of Bim and downregulation of Bcl-2, XIAP, and survivin. These data suggest that Bim is a potential target of 10-chlorocanthin-6-one, further demonstrating its potential use in the prevention and treatment of ovarian cancer.994.
Arabidopsis ANGUSTIFOLIA3 (AN3) is associated with the promoter of CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) to regulate light‐mediated stomatal development 下载免费PDF全文
Lai‐Sheng Meng Cong Li Meng‐Ke Xu Xu‐Dong Sun Wen Wan Xiao‐Ying Cao Jin‐Lin Zhang Kun‐Ming Chen 《Plant, cell & environment》2018,41(7):1645-1656
Light signals are perceived by multiple photoreceptors that converge to suppress the RING E3 ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) for the regulation of stomatal development. Thus, COP1 is a point of integration between light signaling and stomatal patterning. However, how light signaling is collected into COP1 for the production and spacing of stomata is still unknown. Here, we report that the loss‐of‐function mutant of ANGUSTIFOLIA3 (AN3) delays asymmetric cell division, which leads to decreased stomatal index. Furthermore, overexpression of AN3 accelerates asymmetric cell division, which results in clusters of stomata. In addition, the stomatal development through AN3 regulation is mediated by light signaling. Finally, we find that an3 is a light‐signaling mutant, and that AN3 protein is light regulated. Self‐activation by AN3 contributes to the control of AN3 expression. Thus, AN3 is a point of collection between light signaling and stomatal patterning. Target‐gene analysis indicates that AN3 is associated with COP1 promoter for the regulation of light‐controlling stomatal development. Together, these components for regulating stomatal development form an AN3–COP1–E3 ubiquitin ligase complex, allowing the integration of light signaling into the production and spacing of stomata. 相似文献
995.
996.
新生大鼠小肠上皮细胞分离培养研究 总被引:10,自引:2,他引:8
本实验比较了4种分离大鼠IEC的方法,结果显示联合应用粗胶原酶和中性蛋白酶分离效果最好,细胞贴壁生长能力强。胶原涂膜改善玻璃培养瓶或盖玻片表面的性状有利于细胞贴壁生长。细胞的增殖依赖于培养液的质量、成分及细胞间的相互作用。培养细胞一般1~2天贴壁,7~8天明显增殖,10~14天汇合成片。培养细胞细胞角质蛋白、碱性磷酸酶染色阳性,光镜和电镜检查均显示为IEC。本文所建立的新生大鼠IEC体外培养方法为研究IEC生理和病理提供了一个十分有用的实验模型。 相似文献
997.
GKAP, a Novel Synaptic Protein That Interacts with the Guanylate Kinase-like Domain of the PSD-95/SAP90 Family of Channel Clustering Molecules 总被引:15,自引:2,他引:13 下载免费PDF全文
Eunjoon Kim Scott Naisbitt Yi-Ping Hsueh Anuradha Rao Adam Rothschild Ann Marie Craig Morgan Sheng 《The Journal of cell biology》1997,136(3):669-678
The molecular mechanisms underlying the organization of ion channels and signaling molecules at the synaptic junction are largely unknown. Recently, members of the PSD-95/SAP90 family of synaptic MAGUK (membrane-associated guanylate kinase) proteins have been shown to interact, via their NH2-terminal PDZ domains, with certain ion channels (NMDA receptors and K+ channels), thereby promoting the clustering of these proteins. Although the function of the NH2-terminal PDZ domains is relatively well characterized, the function of the Src homology 3 (SH3) domain and the guanylate kinase-like (GK) domain in the COOH-terminal half of PSD-95 has remained obscure. We now report the isolation of a novel synaptic protein, termed GKAP for guanylate kinase-associated protein, that binds directly to the GK domain of the four known members of the mammalian PSD-95 family. GKAP shows a unique domain structure and appears to be a major constituent of the postsynaptic density. GKAP colocalizes and coimmunoprecipitates with PSD-95 in vivo, and coclusters with PSD-95 and K+ channels/ NMDA receptors in heterologous cells. Given their apparent lack of guanylate kinase enzymatic activity, the fact that the GK domain can act as a site for protein– protein interaction has implications for the function of diverse GK-containing proteins (such as p55, ZO-1, and LIN-2/CASK). 相似文献
998.
999.
半夏种内居群形态变异的模糊聚类分析 总被引:15,自引:1,他引:14
在同一栽培条件下,对主要引自长江中下游地区的15个半夏〔Pineliaternata(Thunb.)Breit.〕居群的16个主要形态性状进行模糊聚类分析,在置信水平λ=0.6764时,将15个居群划分成4个类型:(1)双珠芽类型:主要形态特征为叶柄上均具双珠芽,但叶型和块茎形状变异较小;(2)普通类型:主要形态特征为叶柄上均只着生单珠芽,但叶型和块茎形状变异较大;(3)长茎类型:主要形态特征为叶柄上具单珠芽,但着生位置较低,块茎呈矩圆形;(4)复合类型:主要形态特征为叶柄上具单珠芽,但居群内常有双珠芽个体出现。 相似文献
1000.
银缕梅叶器官的宏观与微观结构及系统意义 总被引:2,自引:0,他引:2
银缕梅〔Shaniodendronsubaequale(Chang)Deng,WeietWang〕叶表皮毛为星状毛,气孔器为平列式中周缘型,叶缘齿型为弗特吉型,叶肉栅栏组织一层细胞厚,三叶隙三叶迹的节,从茎节到叶之间的维管束呈分离合并分离的变化格局,并且呈续次合并和续次分离发育模式。这些结果进而说明银缕梅属的独立性,也从一个侧面证明它应属于狭义的弗特吉族(Fothergileae)。 相似文献