Effects of temperature on the expression of STN7 and phosphorylation of LHCII proteins in <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

In Arabidopsis thaliana, STN7 kinase is required for phosphorylation of LHCII and for state transitions. In this paper, a hydrophilic polypeptide, derived from the amino acid sequence of STN7, was conjugated to a carrier protein, bovine serum albumin （BSA）, to obtain the polyclonal antibody. Immunogenicity and specificity of the polyclonal antibody were evaluated by agar gel immunodiffusion （AGID） test and Western blot analysis. The results show that besides the phosphorylation of LHCII proteins, also the expression of STN7 was regulated by temperature conditions. In addition, the change tendency of LHCII proteins phosphorylation was not only coherent with expression of STN7 with respect to increasing temperature, but also closely related to state transitions. These results would provide useful information for studying regulatory mechanism of LHCII proteins phosphorylation and expression of STN7.     

MST1的酵母双杂交及与Salvador体外结合的研究

利用酵母双杂交系统,以鼠M ST 1(M amm alian STE 20-1 ike 1)为诱饵蛋白,在鼠胚胎库中筛选到22个Salvador的片段。通过E.coli表达系统纯化了6个组氨酸(6H is)融合的M ST 1和谷胱甘肽硫转移酶(GST)融合的Salvador,并做体外蛋白质结合实验,进一步证实了两蛋白质相互结合。通过体外激酶活性分析,发现M ST 1并不直接磷酸化Salvador,但是Salvador能够较强地抑制M ST 1对M BP(磷酸丁酯)的磷酸化,提示有可能Salvador通过影响M ST 1的激酶活性来参与了M ST 1介导的细胞凋亡途径。     

复杂网络分析激酶底物信号传递机制

为了研究信号从激酶到达底物蛋白质后的传递机制,本文将磷酸化和蛋白质相互作用结合构建网络,利用复杂网络理论对该网络进行分析.结果发现,底物中存在的社区结构不会只传递特定激酶组的信号,影响网络稳定性的关键节点大多参与肿瘤发生相关的信号途径.     

Regulation of nicotinic acetylcholine receptors by tyrosine kinases in the peripheral and central nervous system: same players, different roles

Nicotinic acetylcholine receptors (nAChRs) exist in many subtypes and are found in the peripheral and central nervous system where they mediate or modulate synaptic transmission. We review how tyrosine phosphorylation and kinases regulate muscle and neuronal nAChRs. Interestingly, although some of the same kinase players interact with the various receptor subtypes, the functional consequences are different. While concerted action of MuSK, Abl- and Src-family kinases (SFKs) regulates the synaptic distribution of nAChRs at the neuromuscular junction, SFKs activate heteromeric neuronal nAChRs in adrenal chromaffin cells, thereby enhancing catecholamine secretion. In contrast, the activity of homomeric neuronal nAChRs, as found in the hippocampus, is negatively regulated by tyrosine phosphorylation and SFKs. It appears that tyrosine kinases provide the means to regulate all nAChRs; but the functional consequences, even those caused by the same kinase family, are specific for each receptor subtype and location. Received 21 February 2006; received after revision 24 July 2006; accepted 30 August 2006     

Cardiac protective role of a novel erythrocyte-derived depressing factor on rats and its Ca~(2+) mechanism

Erythrocyte-derived depressing factor (EDDF) has been extracted from human erythrocytes by our lab for the first time. Our previous research has shown that EDDF is different from those known blood pressure modulators in the body. It may be a new endogenous player. The physiological functions, toxicity, physical and biological properties, existence and tissue distribution as well as biochemical structure have been well studied in our lab[1—4]. Our previous findings indicated that EDDF p…     

微波法制备白芨多糖磷酸酯

以磷酸二氢钠和磷酸氢二钠混合磷酸盐为磷酰化试剂,尿素为催化剂,微波辅助制备白芨多糖磷酸酯,试图寻找一种方便有效的多糖磷酸酯制备方法.考察了反应温度、微波辐射时间、磷酸盐总量和溶液pH值对反应的影响.得到最佳反应条件为:反应温度50°C,pH值为5,辐射时间3min,磷酸盐用量50%,所得产物中磷取代度为1.57%.微波制备方法的反应温度低、时间短、反应物用量小、产物的取代度高,是一种高效的白芨多糖磷酸酯合成方法.     

使用多样性增量预测磷酸化位点

磷酸化是蛋白质最重要的翻译后修饰之一.应用基于多样性增量的二次判别分析 (Increment of Diversity with Quadratic Discriminant analysis,IDQD)方法对CK2,PKA和PKC三种类型磷酸化位点进行预测,k-fold交叉检验的正确率分别为86%,90%和85%,独立测试集检验的正确率分别为86%,88%和84%.所得结果高于包括支持向量机在内的现有预测方法.     

Src activation and translocation from focal adhesions to membrane ruffles contribute to formation of new adhesion sites

Cell migration requires the coordinated turnover of focal adhesions, a process that involves FAK phosphorylation. Since Src is the major kinase implicated in FAK phosphorylation, we focus here on the role of Src activation on adhesion remodelling. In astrocytoma cells, constitutively activated Src induces both FAK phosphorylation and adhesion rearrangement. To evaluate how Src controls these processes, we used a recently described Src reporter to monitor the dynamics of Src phosphorylation. Upon Src activation, focal adhesions started to disassemble while Src appeared highly expressed at newly formed membrane ruffles. Kinetic analysis of time-lapse movies showed that loss of phospho-Src at focal adhesions was time-correlated with the appearance of membrane ruffles containing phospho-Src. Moreover, FLIP analysis revealed a dynamic equilibrium of Src between focal adhesions and membrane ruffles. We conclude that upon phosphorylation, Src is directly translocated from focal adhesions to membrane ruffles, thereby promoting formation of new adhesion complexes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Received 21 July 2008; received after revision 10 October 2008; accepted 03 November 2008