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1.
A G protein-coupled receptor is a plasma membrane receptor for the plant hormone abscisic acid 总被引：4，自引：0，他引：4
The plant hormone abscisic acid (ABA) regulates many physiological and developmental processes in plants. The mechanism of ABA perception at the cell surface is not understood. Here, we report that a G protein-coupled receptor genetically and physically interacts with the G protein alpha subunit GPA1 to mediate all known ABA responses in Arabidopsis. Overexpressing this receptor results in an ABA-hypersensitive phenotype. This receptor binds ABA with high affinity at physiological concentration with expected kinetics and stereospecificity. The binding of ABA to the receptor leads to the dissociation of the receptor-GPA1 complex in yeast. Our results demonstrate that this G protein-coupled receptor is a plasma membrane ABA receptor. 相似文献
2.
Golf: an olfactory neuron specific-G protein involved in odorant signal transduction 总被引：34，自引：0，他引：34
Biochemical and electrophysiological studies suggest that odorants induce responses in olfactory sensory neurons via an adenylate cyclase cascade mediated by a G protein. An olfactory-specific guanosine triphosphate (GTP)-binding protein alpha subunit has now been characterized and evidence is presented suggesting that this G protein, termed Golf, mediates olfaction. Messenger RNA that encodes Golf alpha is expressed in olfactory neuroephithelium but not in six other tissues tested. Moreover, within the olfactory epithelium, Golf alpha appears to be expressed only by the sensory neurons. Specific antisera were used to localize Golf alpha protein to the sensory apparatus of the receptor neurons. Golf alpha shares extensive amino acid identity (88 percent) with the stimulatory G protein, Gs alpha. The expression of Golf alpha in S49 cyc- kin- cells, a line deficient in endogenous stimulatory G proteins, demonstrates its capacity to stimulate adenylate cyclase in a heterologous system. 相似文献
3.
Hu J Shibata Y Voss C Shemesh T Li Z Coughlin M Kozlov MM Rapoport TA Prinz WA 《Science (New York, N.Y.)》2008,319(5867):1247-1250
The tubular structure of the endoplasmic reticulum (ER) appears to be generated by integral membrane proteins, the reticulons and a protein family consisting of DP1 in mammals and Yop1p in yeast. Here, individual members of these families were found to be sufficient to generate membrane tubules. When we purified yeast Yop1p and incorporated it into proteoliposomes, narrow tubules (approximately 15 to 17 nanometers in diameter) were generated. Tubule formation occurred with different lipids; required essentially only the central portion of the protein, including its two long hydrophobic segments; and was prevented by mutations that affected tubule formation in vivo. Tubules were also formed by reconstituted purified yeast Rtn1p. Tubules made in vitro were narrower than normal ER tubules, due to a higher concentration of tubule-inducing proteins. The shape and oligomerization of the "morphogenic" proteins could explain the formation of the tubular ER. 相似文献
4.
Direct activation of mammalian atrial muscarinic potassium channels by GTP regulatory protein Gk 总被引：41，自引：0，他引：41
The mammalian heart rate is regulated by the vagus nerve, which acts via muscarinic acetylcholine receptors to cause hyperpolarization of atrial pacemaker cells. The hyperpolarization is produced by the opening of potassium channels and involves an intermediary guanosine triphosphate-binding regulatory (G) protein. Potassium channels in isolated, inside-out patches of membranes from atrial cells now are shown to be activated by a purified pertussis toxin-sensitive G protein of subunit composition alpha beta gamma, with an alpha subunit of 40,000 daltons. Thus, mammalian atrial muscarinic potassium channels are activated directly by a G protein, not indirectly through a cascade of intermediary events. The G protein regulating these channels is identified as a potent Gk; it is active at 0.2 to 1 pM. Thus, proteins other than enzymes can be under control of receptor coupling G proteins. 相似文献
5.
[目的]筛选可结合Caco-2细胞表面蛋白的副溶血弧菌外膜蛋白。[方法]筛选副溶血弧菌外膜中的黏附蛋白,将Caco-2细胞表面蛋白生物素化并固定于中性卵白素树脂上,进一步利用亲和层析技术来筛选副溶血弧菌的外膜蛋白。[结果]通过LC-MS/MS质谱技术鉴定出3个候选蛋白:ATP synthase subunit alpha、ATP synthase subunit beta和outer membrane protein U。通过对这3个蛋白进行克隆基因和原核表达,成功纯化得到相应重组蛋白。通过进一步的间接免疫荧光试验,发现3种蛋白对于Caco-2细胞均有黏附作用。[结论]推测ATP synthase subunit alpha、ATP synthase subunit beta和outer membrane protein U这3种蛋白可能是潜在的黏附因子。 相似文献
6.
The insulin receptor contains a calmodulin-binding domain 总被引：3，自引：0，他引：3
Substantial evidence suggests that calcium has a pivotal role in regulating the initial events through which insulin alters plasma membrane metabolism. Because binding of insulin to its receptor represents the initial site of insulin action in the plasma membrane, studies were undertaken to determine whether the insulin receptor is a calmodulin-binding protein. Preparations enriched in the insulin receptor and calmodulin-binding proteins were isolated from detergent-solubilized rat adipocyte membranes by chromatography with wheat germ agglutinin agarose and calmodulin-conjugated Sepharose, respectively. Substantial purification of a manganese-dependent, insulin-sensitive phosphoprotein of 95K identified as the beta subunit of the insulin receptor was accomplished. Binding and photocovalent cross-linking of iodine-125-labeled calmodulin to these affinity-purified preparations and to isolated plasma membranes, followed by immunoadsorption with insulin receptor antibodies bound to protein A Sepharose, resulted in significant purification of a binding complex of 110K to 140K. These results indicate that the adipocyte insulin receptor or a polypeptide closely associated with the receptor is a calmodulin-binding protein. 相似文献
7.
A G protein directly regulates mammalian cardiac calcium channels 总被引：45，自引：0，他引：45
A Yatani J Codina Y Imoto J P Reeves L Birnbaumer A M Brown 《Science (New York, N.Y.)》1987,238(4831):1288-1292
A possible direct effect of guanine nucleotide binding (G) proteins on calcium channels was examined in membrane patches excised from guinea pig cardiac myocytes and bovine cardiac sarcolemmal vesicles incorporated into planar lipid bilayers. The guanosine triphosphate analog, GTP gamma S, prolonged the survival of excised calcium channels independently of the presence of adenosine 3',5'-monophosphate (cAMP), adenosine triphosphate, cAMP-activated protein kinase, and the protein kinase C activator tetradecanoyl phorbol acetate. A specific G protein, activated Gs, or its alpha subunit, purified from the plasma membranes of human erythrocytes, prolonged the survival of excised channels and stimulated the activity of incorporated channels. Thus, in addition to regulating calcium channels indirectly through activation of cytoplasmic kinases, G proteins can regulate calcium channels directly. Since they also directly regulate a subset of potassium channels, G proteins are now known to directly gate two classes of membrane ion channels. 相似文献
8.
Protein-tyrosine kinase activity in Saccharomyces cerevisiae 总被引：14，自引：0，他引：14
Saccharomyces cerevisiae was examined for tyrosine kinase activity in vitro because this organism offers molecular and genetic approaches for analyzing the role of tyrosine phosphorylation in cellular growth control that are unavailable in higher eukaryotes. Yeast extracts phosphorylated a random copolymer (glutamic acid:tyrosine, 80:20) at tyrosine in a reaction that was linear with respect to time and protein concentration. In the absence of added copolymer, phosphotyrosine was 0.1 percent of the total phosphoamino acids labeled with [gamma-32P]adenosine triphosphate in endogenous yeast proteins. However, specific activities of these reactions were low (approximately 1 percent of those in extracts of chick embryo fibroblasts). Lack of significant incorporation of label from [alpha-32P]adenosine triphosphate into the copolymer or endogenous yeast proteins demonstrated that nucleotide interconversion, adenylylation, and subsequent hydrolysis could not account for the generation of phosphotyrosine observed. 相似文献
9.
【目的】研究MbNramp1基因的功能。【方法】通过异源互补试验鉴定该基因转运铁的功能,并对MbNRAMP1蛋白进行亚细胞定位研究。【结果】MbNramp1基因转化酵母突变株DDY4在缺铁的培养基上恢复生长。在供试BPDS浓度的培养基上,MbNramp1基因转化酵母突变株DDY4生长状况均明显好于空载体转化后的突变株。培养基中BPDS增加到15μmol·L-1时,转化了MbNramp1的酵母细胞生长状况与野生型相差无几。在30μmol·L-1BPDS时,MbNramp1转化的细胞与低浓度BPDS相比生长延缓,但是明显优于空载体转化的DDY4突变株。与较低浓度BPDS相比,野生型酵母(DY1457)的生长量也减少了。亚细胞定位表明,MbNRAMP1主要位于部分质膜上而非整个膜上。【结论】初步证明MbNramp1编码具有功能的铁转运蛋白,能够使酵母吸收铁的突变株恢复突变,MbNRAMP1主要位于部分细胞膜上行使铁营养转运功能。 相似文献
10.
The mating response of the budding yeast Saccharomyces cerevisiae is mediated by a prototypical heterotrimeric GTP-binding protein (G protein) and mitogen-activated protein kinase (MAPK) cascade. Although signal transmission by such pathways has been modeled in detail, postreceptor down-regulation is less well understood. The pheromone-responsive G protein alpha subunit (Galpha) of yeast down-regulates the mating signal, but its targets are unknown. We have found that Galpha binds directly to the mating-specific MAPK in yeast cells responding to pheromone. This interaction contributes both to modulation of the mating signal and to the chemotropic response, and it demonstrates direct communication between the top and bottom of a Galpha-MAPK pathway. 相似文献
11.
Chen JG Willard FS Huang J Liang J Chasse SA Jones AM Siderovski DP 《Science (New York, N.Y.)》2003,301(5640):1728-1731
G protein-coupled receptors (GPCRs) at the cell surface activate heterotrimeric G proteins by inducing the G protein alpha (Galpha) subunit to exchange guanosine diphosphate for guanosine triphosphate. Regulators of G protein signaling (RGS) proteins accelerate the deactivation of Galpha subunits to reduce GPCR signaling. Here we identified an RGS protein (AtRGS1) in Arabidopsis that has a predicted structure similar to a GPCR as well as an RGS box with GTPase accelerating activity. Expression of AtRGS1 complemented the pheromone supersensitivity phenotype of a yeast RGS mutant, sst2Delta. Loss of AtRGS1 increased the activity of the Arabidopsis Galpha subunit, resulting in increased cell elongation in hypocotyls in darkness and increased cell production in roots grown in light. These findings suggest that AtRGS1 is a critical modulator of plant cell proliferation. 相似文献
12.
【目的】对小反刍兽疫病毒（Peste des petits ruminants virus,PPRV）H蛋白胞外区（tH）细胞膜受体进行鉴定,为PPRV致病机制的研究奠定基础。【方法】克隆PPRV H基因胞外区（tH）,在毕赤酵母(Pichia pastoris)中进行真核表达,纯化后免疫家兔,获得兔抗PPRVtH蛋白特异性抗体;提取山羊外周血淋巴细胞膜蛋白,经SDS-PAGE检测后,湿转印法转印至NC膜,分别利用纯化的重组tH蛋白和PPRV进行病毒铺覆蛋白结合试验（VOPBA）,对受体进行鉴定。【结果】成功克隆了1 653 bp的PPRV tH基因,构建其重组酵母表达质粒pPIC9K-tH,诱导表达后获得了60 ku目的蛋白。重组tH蛋白免疫家兔后获得了效价为1∶200的抗血清。Westernblotting分析发现,该重组蛋白可与PPRV多克隆抗体发生特异性反应,山羊外周血淋巴细胞膜蛋白上有2个与PPRV和重组tH蛋白结合的蛋白带,分子质量约为38和100 ku。【结论】从山羊外周血淋巴细胞膜蛋白上鉴定到了2种与PPRV结合的蛋白组分,其特性有待于进一步研究。 相似文献
13.
Production of an epidermal growth factor receptor-related protein 总被引：24，自引：0，他引：24
Human epidermoid carcinoma A431 cells in culture produce a soluble 105-kilodalton protein which, by the criteria of epidermal growth factor (EGF) binding, recognition by monoclonal and polyclonal antibodies to the EGF receptor, amino-terminal sequence analysis and carbohydrate content, is related to the cell surface domain of the EGF receptor. The high rate of production and the finding that with biosynthetic labeling the specific activity of this 105-kilodalton protein exceeds that of the intact receptor indicate that it is not derived from membrane-bound mature receptor but is separately produced by the cell. These cells thus separately synthesize an EGF receptor that is inserted into the membrane and an EGF receptor-related protein that is secreted. 相似文献
14.
Betzig E Patterson GH Sougrat R Lindwasser OW Olenych S Bonifacino JS Davidson MW Lippincott-Schwartz J Hess HF 《Science (New York, N.Y.)》2006,313(5793):1642-1645
We introduce a method for optically imaging intracellular proteins at nanometer spatial resolution. Numerous sparse subsets of photoactivatable fluorescent protein molecules were activated, localized (to approximately 2 to 25 nanometers), and then bleached. The aggregate position information from all subsets was then assembled into a superresolution image. We used this method--termed photoactivated localization microscopy--to image specific target proteins in thin sections of lysosomes and mitochondria; in fixed whole cells, we imaged vinculin at focal adhesions, actin within a lamellipodium, and the distribution of the retroviral protein Gag at the plasma membrane. 相似文献
15.
Direct demonstration of impaired functionality of a purified desensitized beta-adrenergic receptor in a reconstituted system 总被引：4，自引：0，他引：4
B Strulovici R A Cerione B F Kilpatrick M G Caron R J Lefkowitz 《Science (New York, N.Y.)》1984,225(4664):837-840
Long-term exposure of various cell types to beta-adrenergic agonists such as isoproterenol leads to an attenuated responsiveness ("desensitization") of the adenylate cyclase system to further challenge with these agonists. The turkey erythrocyte model system was used earlier to show that a covalent modification of the receptor (phosphorylation) is associated with this process. The functionality of the "desensitized" beta-adrenergic receptor was assessed by implanting purified beta-adrenergic receptor preparations from control and desensitized turkey erythrocytes into phospholipid mixtures and then fusing them with receptor-deficient cells (Xenopus laevis erythrocytes). Desensitized beta-adrenergic receptors showed a 40 to 50 percent reduction in their ability to couple to the heterologous adenylate cyclase system, comparable to the reduction in their functionality observed in their original membrane environment. These results demonstrate the utility of recently developed receptor reconstitution techniques for assessing the functionality of purified receptors and show a direct link between a covalent modification of a membrane-bound receptor and its impaired functionality in a reconstituted system. 相似文献
16.
To investigate the potential effects of Vaccaria segetalis, we employed the proteomic approach on the dairy cow mammary gland epithelial cells (DCMECs). A total of 35 differentially expressed nuclear proteins were visualized by 2-DE and silver nitrate staining. Of these, five proteins also displayed significant expression changes upon treatment of the water decoction from Vaccaria segetalis, and such alterations were further confirmed by RT-PCR. Together, at both the mRNA and protein levels, the water decoction from Vaccaria segetalis increased the expression of proteins ethylmalonic encephalopathy 1 (ETHE1), vesicle amine transport protein 1 homolog (VAT1), parkinson disease protein 7 homolog (Protein DJ-1), proteasome subunit alpha type-2 (PSMA2) and SUMO-activating enzyme subunit 1 (SAE1). This study would enable a better understanding of the molecular mechanisms underlying this water decoction effects at the protein level. 相似文献
17.
Salmonella enterica causes a variety of diseases, including gastroenteritis and typhoid fever. The success of this pathogen depends on its capacity to proliferate within host cells in a membrane-bound compartment. We found that the Salmonella-containing vacuole recruited the plus-end-directed motor kinesin. Bacterial effector proteins translocated into the host cell by a type III secretion system antagonistically regulated this event. Among these effectors, SifA targeted SKIP, a host protein that down-regulated the recruitment of kinesin on the bacterial vacuole and, in turn, controlled vacuolar membrane dynamics. 相似文献
18.
19.
Platelet membrane glycoprotein IIb/IIIa: member of a family of Arg-Gly-Asp--specific adhesion receptors 总被引：99，自引：0，他引：99
R Pytela M D Pierschbacher M H Ginsberg E F Plow E Ruoslahti 《Science (New York, N.Y.)》1986,231(4745):1559-1562
Adhesive interactions of the platelet surface with plasma proteins such as fibrinogen and fibronectin play an important role in thrombosis and hemostasis. The binding of both of these proteins to platelets is inhibited by synthetic peptides containing the sequence Arg-Gly-Asp, which corresponds to the cell adhesion site in fibronectin and is also present in the alpha chain of fibrinogen. An affinity matrix made of an insolubilized heptapeptide containing the Arg-Gly-Asp sequence selectively binds the platelet membrane glycoprotein IIb/IIIa from detergent extracts of platelets. When incorporated into liposome membranes, the isolated protein confers to the liposomes the ability to bind to surfaces coated with fibrinogen, fibronectin, and vitronectin but not to surfaces coated with thrombospondin or albumin. This platelet receptor is related to the previously identified fibronectin and vitronectin receptors in that it recognizes an Arg-Gly-Asp sequence but differs from the other receptors in its wider specificity toward various adhesive proteins. These results establish the existence of a family of adhesion receptors that recognize the sequence Arg-Gly-Asp. 相似文献
20.
Molecular cloning of complementary DNA for the alpha subunit of the G protein that stimulates adenylate cyclase 总被引：27，自引：0，他引：27
A complementary DNA clone encoding the alpha subunit of the adenylate cyclase stimulatory G protein (Gs) was isolated and identified. A bovine brain complementary DNA library was screened with an oligonucleotide probe derived from amino acid sequence common to known G proteins. The only clone that was obtained with this probe has a complementary DNA insert of approximately 1670 base pairs. An antibody to a peptide synthesized according to deduced amino acid sequence reacts specifically with the alpha subunit of Gs. In addition, RNA that hybridizes with probes made from the clone is detected in wild-type S49 cells; however, cyc- S49 cells, which are deficient in Gs alpha activity, are devoid of this messenger RNA. 相似文献