Structure and function of polyamine transport systems and NMDA receptors

1.研究了酿酒酵母中多胺的转运。（1）TPO 1位于细胞膜上，催化多胺的分泌。TPO 1的转运活性通过酪蛋白激酶1在Ser ^蛋白激酶C和Thr ^的磷酸化而增强。<19><52>通过cAMP依赖性蛋白激酶1和2在Ser ^处的磷酸化，TPO 1从内质网到质膜的分选得到增强。<342>（2）YKL 174c编码的TPO 5催化腐胺和亚精胺的分泌，并定位于高尔基体或高尔基体后的分泌囊泡上，提示TPO 5参与了多胺的分泌和内吞途径。(3)We发现尿素转运蛋白DUR3和S-腺苷甲硫氨酸转运蛋白SAM3位于质膜上，优先催化多胺的摄取，并且在培养基中多胺的存在抑制了这两种mRNA的表达。 ...更多信息 感受器，参与中枢神经系统的可塑性。研究了不同蒽醌多胺（AQP）对非洲爪蟾卵母细胞表达的NMDA受体的影响。所有AQP衍生物均抑制卵母细胞NR1/NR2受体在-70 mV电压钳制下的反应。该阻滞具有很强的电压依赖性。AQ亚精胺（AQ34）抑制NR1/NR2受体的反应，但不抑制AMPA受体的反应，表明AQ34是优选的NMDA受体拮抗剂。使用突变体NR1和NR2亚基的实验结果鉴定了影响AQ34阻断的残基。这些残留物位于选择性过滤器/通道最西收缩处的外前庭和选择性过滤器水平以下的内前庭。纯化了NMDA受体亚基的调节结构域（R-结构域）蛋白，并测定了蛋白的性质。这表明精胺和艾芬地尔在R结构域蛋白上的结合位点是不同的。少

1.Polyamine transport in Saccharomyces cerevisiae was studied. (1)TPO1, located on the plasma membrane, catalyzed the excretion of polyamines. The transport activity of TPO1 was enhanced through phosphorylation at Ser^<19> protein kinase C and at Thr^<52> by casein kinase 1. Sorting of TPO1 from the endoplasmic reticulum to the plasma membrane was enhanced through phosphorylation at Ser^<342> by cAMP dependent protein kinases 1 and 2. (2)TPO5 encoded by YKL174c catalyzed the excretion of putrescine and spermidine, and it was localized on Golgi or post-Golgi secretory vesicles, suggesting that secretory and endocytic pathways, are involved in the excretion of polyamines by TPO5. (3)We found that urea transporter DUR3 and S-adenosylmethionine transporter SAM3, located on plasma membrane, catalyze polyamine uptake preferentially, and that the expression of both mRNAs were repressed by the presence of polyamines in medium.2.NMDA (N-methyl-D-aspartate) receptor is a subtype of glutamate rec … More eptors and involved in the plasticity of central nerves system. The effects of various anthraquinone polyamines (AQP) were studied at NMDA receptors expressed in Xenopus laevis oocytes. All AQP derivatives inhibited responses of NR1/NR2 receptors in oocytes voltage-clamped at -70 mV. The block was strongly voltage-dependent. AQ spermidine (AQ34) inhibited responses of NR1/NR2 receptors but did not inhibit responses of AMPA receptors indicating that AQ34 is preferential NMDA antagonists. Results of experiments using mutant NR1 and NR2 subunits identified residues that influence block by AQ34. These residues are located in the outer vestibule at the selectivity filter/narrowest constriction of the channel and in the inner vestibule below the level of the selectivity filter. Regulatory domain (R-domain) proteins of NMDA receptor subunits were purified and the properties of the proteins were determined. It was suggested that binding sites of spermine and ifenprodil on R-domain proteins are different each other. Less