The new sideway of CNTF signal transduction pathway

The action of ciliary neurotrophic factor (CNTF) on intercellular free Ca²⁺ concentrations [Ca²⁺]_i induced by glutamate (Glu) in primary cultured hippocampal neurons were detected with Fura2/AM, a Ca²⁺-sensitive fluorophore, and the morphological influence of G-protein on it was objected. Glu could induce rapid increase of [Ca²⁺]_i in hippocampal neurons. CNTF had no significant action on [Ca²⁺]_i in resting hippocampal neurons. However, after incubation of CNTF for 5 min, the increase of [Ca²⁺]_i in hippocampal neurons rapidly induced by Glu was inhibited. Pretussis toxin (PTX)-sensitive G protein could block the action. These results indicate that a new non-genomic rapid sideway might exist in the upper stream of CNTF signal transduction pathway, which was related to Ca²⁺ signal transduction. Keywords:     

Cell cycle and cell signal transduction in marine phytoplankton

tAs unicellular phytoplankton, the growth of a marine phytoplankton population results directly from the completion of a cell cycle, therefore, cell-environment communication is an important way which involves signal transduction pathways to regulate cell cycle progression and contribute to growth, metabolism and primary production and respond to their surrounding environment in marine phytoplankton. Cyclin-CDK and CaM/Ca²⁺ are essentially key regulators in control of cell cycle and signal transduction pathway, which has important values on both basic research and applied biotechnology. This paper reviews progress made in this research field, which involves the identification and characterization of cyclins and cell signal transduction system, cell cycle-control mechanisms in marine phytoplankton cells, cell cycle proteins as a marker of a terminal event to estimate the growth rate of phytoplankton at the species level, cell cycle-dependent toxin production of toxic algae and cell cycle progression regulated by environmental factors.     

Brassinosteroid signal transduction: An emerging picture

Brassinosteroids (BRs) are plant steroid hormones that have similar structures and functions with Brassino-lide (BL). BR signaling is complicated, and the input of BR signal is under fine control. The active BR level is regulated at the levels of BR biosynthesis and metabolic inactivation[1,2]. BR biosynthetic pathway consists of a metabolic grid, and the expression of several genes for BR biosynthesis is feedback regulated by BR signaling[3,4]. The sequential events of BR action inclu…     

一氧化氮的细胞内信号转导

本文从一氧化氮/环鸟苷酸途径;激活环氧化酶;调节蛋白激酶C;影响转录因子等多个方面对一氧化氮(NO)的细胞内信号转导途径进行了阐述.     

植物抗病性的分子机制和信号传导

植物抗病性的分子机制一直是植物病理学关注的焦点.近年来,国内外不少学者和实验室正在大量分离和培养与抗病有关的突变体,并且寻找和研究与抗病有关的基因和抗病机制.研究表明,在病原物与植物的相互作用、病原信号的传导和抗病性激发的过程中存在着一系列的调节因子和基因,并形成复杂的调控网络.综述了近年来国内外植物抗病性的分子研究进展,阐述了植物抗病性分子机制和信号传导.     

Cytokinin signal transduction： Known simplicity and unknown complexity

Cytokinin plays a critical role in plant growth and development by regulating cell divisions and cell differentiation. Recent studies suggest that cytokinin signaling is presumably mediated by a two-component system analogous to those found in bacteria and fungi, which transduces an external signal via a phosphorelay from the plasma membrane-anchored receptors to downstream effectors and regulators. Moreover, cytokinin signaling is highly interactive with other pathways, and many components of the pathway appear to be functionally redundant. Proper address of these questions will be crucial for our further understanding on this important network.     

Regulation between nitric oxide and MAPK signal transduction in mammals

Nitric oxide (NO) is an important biological messenger in the regulation of tissue homeostasis. It exhibits a wide range of effects during physiological and pathophysiological processes. Typical beneficial properties of NO include the regulation of vascular tone,the protection of cells against apoptosis, the modulation of immune responses, and the killing of microbial pathogens. On the other hand,NO may cause severe vasodilation and myocardial depression during bacterial sepsis or act as a cytotoxic and tissue-damaging molecule in autoimmune diseases. Mitogen-activated protein kinase (MAPK) is a family of serine/threonine protein kinases that are widely distributed in mammalian cells. MAPK cascade plays pivotal roles in gene expression, cell proliferation, differentiation, neuronal survival and programmed cell death under a variety of experimental conditions. MAPKs transduce the signal for the cellular response to extracellular stresses or stimuli. The relation between them, however, has never been reviewed. Based on our researches and other reports in the field, we review their reciprocal regulatory functions.     

Role of acetylcholine on plant root-shoot signal transduction

The role of accetylcholine (ACh) on plant root-shoot communication was investigated using the root-split system of Vicia faba L.In the experiments,slight osmotic stress caused the decrease of ACh content in root tips and the xylem sap transported up per time unit from root tip to the shool when the water potential of the shoot was kept unchanged .It also caused the decrease of ACh content in the abaxial epidermis,The decrease was highly correlative to the changes of transpiration rate,suggesting that the decrase of ACh content probably functions as a signal to regulate stomatal behavior,The effect of osmotic stress might be mainly through the inhibition of the ACh synthesis in root tip ;thus further influences the ACh content in root tip ,xylem sap and abaxial epidermis and resulting in the changes of stomata behavior,These results provide new evdence that plants transduce positive and negative signals among roots and shoot to coordinate stomatal behavior and adapt to variable environments.     

Involvement of Ca<Superscript>2+</Superscript>/CaM in the signal transduction of acetylcholine regulating stomatal movement

It has been known that the neurotransmitter acetylcholine (ACh) also exists in plants and is able to regulate the movement of stomata.In another aspect,Ca^2 /CaM as the second messengers have a critical role of signal transduction in stomatal guard-cell,Here we showed that Ca^2 /CaM were also involved in the ACh regulated stomatal movement,In the medium containing Ca^2 ,the Ca^2 channel blockers (NIF and Ver)and CaM inhibitors (TFP and W7 ) could neutralize the ACh induced stomatal opening,however,they are ineffective in the medium containing K^ ,Those results indicated that Ca^2 /CaM were involved in the signal transduction pathway of ACh regulating stomatal movement.     

植物在渗透胁迫下信号转导的级联机制

研究植物在渗透胁迫下信号转导的级联机制,对于有效调控植物在逆境中的生长发育,提高其抗逆性和生存能力具有重要的指导意义．根据近年来国内外的研究成果和报道,综述了植物细胞在渗透胁迫下感受到信号后,相继产生许多信号分子,这些信号分子通过细胞壁-质膜-细胞骨架连续体,引起细胞骨架蛋白变构而传递信息,并与细胞膜蛋白、第二信使系统以及调节因子构成了信号传递网,最终有条不紊地引起特定的基因表达和应答．     

蓝藻真核型蛋白质激酶与信号传导

对最近10年在蓝藻中找到大量编码Ser／Thr基因的研究结果进行了综述,并对这些蛋白质激酶在信号传导中的作用模式做了讨论．     

Cloning and identification of a novel binding protein of CD2 cytoplasmic domain

In order to understand why CD2 has a dual action of transduction of activation or apoptosis signals in T cells under different experimental conditions, we employed a yeast two-hybrid system to look for a binding protein of the cytoplasmic domain of CD2 which may be involved in this issue. A human T cell cDNA library was screened by a cDNA encoding the cytoplasmic domain of CD2 (Thr211-Gln336). The specificity of protein-protein interaction was verified by co-immunoprecipitation. The binding protein obtained, designated CD2cBP, was found to be homologous tov-fos transformation effector protein (Fte-1). As Fte-1 plays a role in cell transformation, growth, protein synthesis and protein-import into mitochondria, this result suggests that CD2cBP may be putatively involved in CD2-mediated signaling.     

Cloning and identification of a novel human glioma differentiation related geneGDR1

In order to identify the genes associated with glioblastoma differentiation, some ESTs, expressed differentially in the control cell and the differentiated human glioblastoma cell line BT-325 induced by the all-trans retinoid acid, have been isolated by the method of DDRT-PCR. Of the 46 ESTs sequenced, 19 are from new genes. A full-length 1 535-bp cDNA, termed geneGDR1, has been isolated from the human cDNA library using the probe designed according to one of the novel ESTs, HGBB098. The open reading frame ofGDR1 gene encodes a putative protein containing 334 amino acid residues. Blast against the current GenBank DNA and protein sequence database did not reveal significant homology with any known proteins. RT-PCR shows thatGDR1 mRNA level increased in the differentiated BT-325 cells after being treated with RA. The different expression patterns ofGDR1 mRNA in human tissues have been detected through the multiple tissue Northern blot hybridization.