共查询到20条相似文献，搜索用时 31 毫秒
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Kovacs JJ Whalen EJ Liu R Xiao K Kim J Chen M Wang J Chen W Lefkowitz RJ 《Science (New York, N.Y.)》2008,320(5884):1777-1781
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Chen W Ren XR Nelson CD Barak LS Chen JK Beachy PA de Sauvage F Lefkowitz RJ 《Science (New York, N.Y.)》2004,306(5705):2257-2260
Binding of Sonic Hedgehog (Shh) to Patched (Ptc) relieves the latter's tonic inhibition of Smoothened (Smo), a receptor that spans the cell membrane seven times. This initiates signaling which, by unknown mechanisms, regulates vertebrate developmental processes. We find that two molecules interact with mammalian Smo in an activation-dependent manner: G protein-coupled receptor kinase 2 (GRK2) leads to phosphorylation of Smo, and beta-arrestin 2 fused to green fluorescent protein interacts with Smo. These two processes promote endocytosis of Smo in clathrin-coated pits. Ptc inhibits association of beta-arrestin 2 with Smo, and this inhibition is relieved in cells treated with Shh. A Smo agonist stimulated and a Smo antagonist (cyclopamine) inhibited both phosphorylation of Smo by GRK2 and interaction of beta-arrestin 2 with Smo. beta-Arrestin 2 and GRK2 are thus potential mediators of signaling by activated Smo. 相似文献
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The Hedgehog (Hh) family of secreted signaling proteins is a master regulator of cell fate determination in metazoans, contributing to both pattern formation during embryonic development and postembryonic tissue homeostasis. In a universally used mode of action, graded distribution of Hh protein induces differential cell fate in a dose-dependent manner in cells that receive Hh. Though much of this pathway has been elucidated from genetically based studies in model organisms, such as Drosophila and mice, the importance of Hh-mediated signaling in humans is clearly evident from malformations and a broad range of cancers that arise when the pathway is corrupted. 相似文献
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Lum L Yao S Mozer B Rovescalli A Von Kessler D Nirenberg M Beachy PA 《Science (New York, N.Y.)》2003,299(5615):2039-2045
Classical genetic screens can be limited by the selectivity of mutational targeting, the complexities of anatomically based phenotypic analysis, or difficulties in subsequent gene identification. Focusing on signaling response to the secreted morphogen Hedgehog (Hh), we used RNA interference (RNAi) and a quantitative cultured cell assay to systematically screen functional roles of all kinases and phosphatases, and subsequently 43% of predicted Drosophila genes. Two gene products reported to function in Wingless (Wg) signaling were identified as Hh pathway components: a cell surface protein (Dally-like protein) required for Hh signal reception, and casein kinase 1alpha, a candidate tumor suppressor that regulates basal activities of both Hh and Wg pathways. This type of cultured cell-based functional genomics approach may be useful in the systematic analysis of other biological processes. 相似文献
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Alvarez JI Dodelet-Devillers A Kebir H Ifergan I Fabre PJ Terouz S Sabbagh M Wosik K Bourbonnière L Bernard M van Horssen J de Vries HE Charron F Prat A 《Science (New York, N.Y.)》2011,334(6063):1727-1731
The blood-brain barrier (BBB) is composed of tightly bound endothelial cells (ECs) and perivascular astrocytes that regulate central nervous system (CNS) homeostasis. We showed that astrocytes secrete Sonic hedgehog and that BBB ECs express Hedgehog (Hh) receptors, which together promote BBB formation and integrity during embryonic development and adulthood. Using pharmacological inhibition and genetic inactivation of the Hh signaling pathway in ECs, we also demonstrated a critical role of the Hh pathway in promoting the immune quiescence of BBB ECs by decreasing the expression of proinflammatory mediators and the adhesion and migration of leukocytes, in vivo and in vitro. Overall, the Hh pathway provides a barrier-promoting effect and an endogenous anti-inflammatory balance to CNS-directed immune attacks, as occurs in multiple sclerosis. 相似文献
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Patched1 regulates hedgehog signaling at the primary cilium 总被引：1，自引：0，他引：1
Primary cilia are essential for transduction of the Hedgehog (Hh) signal in mammals. We investigated the role of primary cilia in regulation of Patched1 (Ptc1), the receptor for Sonic Hedgehog (Shh). Ptc1 localized to cilia and inhibited Smoothened (Smo) by preventing its accumulation within cilia. When Shh bound to Ptc1, Ptc1 left the cilia, leading to accumulation of Smo and activation of signaling. Thus, primary cilia sense Shh and transduce signals that play critical roles in development, carcinogenesis, and stem cell function. 相似文献
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Dishevelled 2 recruits beta-arrestin 2 to mediate Wnt5A-stimulated endocytosis of Frizzled 4 总被引：1，自引：0，他引：1
Chen W ten Berge D Brown J Ahn S Hu LA Miller WE Caron MG Barak LS Nusse R Lefkowitz RJ 《Science (New York, N.Y.)》2003,301(5638):1391-1394
Wnt proteins, regulators of development in many organisms, bind to seven transmembrane-spanning (7TMS) receptors called frizzleds, thereby recruiting the cytoplasmic molecule dishevelled (Dvl) to the plasma membrane.Frizzled-mediated endocytosis of Wg (a Drosophila Wnt protein) and lysosomal degradation may regulate the formation of morphogen gradients. Endocytosis of Frizzled 4 (Fz4) in human embryonic kidney 293 cells was dependent on added Wnt5A protein and was accomplished by the multifunctional adaptor protein beta-arrestin 2 (betaarr2), which was recruited to Fz4 by binding to phosphorylated Dvl2. These findings provide a previously unrecognized mechanism for receptor recruitment of beta-arrestin and demonstrate that Dvl plays an important role in the endocytosis of frizzled, as well as in promoting signaling. 相似文献
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McDonald PH Chow CW Miller WE Laporte SA Field ME Lin FT Davis RJ Lefkowitz RJ 《Science (New York, N.Y.)》2000,290(5496):1574-1577
beta-Arrestins, originally discovered in the context of heterotrimeric guanine nucleotide binding protein-coupled receptor (GPCR) desensitization, also function in internalization and signaling of these receptors. We identified c-Jun amino-terminal kinase 3 (JNK3) as a binding partner of beta-arrestin 2 using a yeast two-hybrid screen and by coimmunoprecipitation from mouse brain extracts or cotransfected COS-7 cells. The upstream JNK activators apoptosis signal-regulating kinase 1 (ASK1) and mitogen-activated protein kinase (MAPK) kinase 4 were also found in complex with beta-arrestin 2. Cellular transfection of beta-arrestin 2 caused cytosolic retention of JNK3 and enhanced JNK3 phosphorylation stimulated by ASK1. Moreover, stimulation of the angiotensin II type 1A receptor activated JNK3 and triggered the colocalization of beta-arrestin 2 and active JNK3 to intracellular vesicles. Thus, beta-arrestin 2 acts as a scaffold protein, which brings the spatial distribution and activity of this MAPK module under the control of a GPCR. 相似文献
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The Wnt-Wingless (Wg) pathway is one of a core set of evolutionarily conserved signaling pathways that regulates many aspects of metazoan development. Aberrant Wnt signaling has been linked to human disease. In the present study, we used a genomewide RNA interference (RNAi) screen in Drosophila cells to screen for regulators of the Wnt pathway. We identified 238 potential regulators, which include known pathway components, genes with functions not previously linked to this pathway, and genes with no previously assigned functions. Reciprocal-Best-Blast analyses reveal that 50% of the genes identified in the screen have human orthologs, of which approximately 18% are associated with human disease. Functional assays of selected genes from the cell-based screen in Drosophila, mammalian cells, and zebrafish embryos demonstrated that these genes have evolutionarily conserved functions in Wnt signaling. High-throughput RNAi screens in cultured cells, followed by functional analyses in model organisms, prove to be a rapid means of identifying regulators of signaling pathways implicated in development and disease. 相似文献
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以草莓为试材,基于拟南芥(Arabidopsis thaliana)、人(Homo sapiens)和家鼠(Mus musculus)等数据库信息,采用同源比对方法,结合ClustalX 2.0序列比对及MEGA 5.0系统进化树分析,对草莓基因组中7TMR的基础生物信息进行了分析。结果表明,草莓基因组中含有84个7TMR,包括23个亚家族。半定量RT-PCR分析表明,该家族全部成员中有33个成员随果实发育表达量明显上调,17个成员表达量明显下调;Real-time PCR分析进一步确认,部分7TMR成员的基因表达与果实发育及成熟过程的整个进程有着密切的关系。此外还发现,草莓中7TMR家族中含有一类特殊的亚家族蛋白,该亚家族与人和家鼠中的脂联素受体高度同源,表明草莓中7TMR存在着非G-蛋白偶联信号转导途径。草莓中类似脂联素受体亚家族ADIPOR包含5个成员,对这5个成员的时空表达和刺激应答进行了分析,发现其中某些成员不仅与果实发育进程关系密切,且对糖信号应答,暗示着该类蛋白在草莓果实发育和成熟调控中可能起着重要作用。 相似文献
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为阐明cilp基因在斑马鱼椎骨和肌间骨发育中的作用,利用CRISPR/Cas9建立了斑马鱼cilp基因敲除纯合突变系（cilp-/-）,对其进行了骨骼表型的观察,并进一步采用qRT-PCR分析了14个骨骼发育相关基因在突变体胚胎发育阶段和成鱼骨骼中的表达水平变化。结果显示,与野生型斑马鱼相比,90 dph（days post hatched）cilp-/-斑马鱼的肌间骨数量显著减少了10.27%（P<0.05）,而肌间骨的长度无明显变化;同时突变体斑马鱼中椎骨发生异常融合及髓棘缺失。qRT-PCR结果显示,与野生型相比,col1a1a、sp7、smad4a和smad5基因在胚胎发育的整个时期都存在显著的差异（P<0.01）;在突变体成鱼尾部骨骼组织中bmp2a、bmp2b、smad5、sp7、runx2a、runx2b和bglap基因的表达量均显著低于野生型,表明cilp基因敲除导致了BMPs和SMADs家族基因的表达水平下降,并下调了下游的成骨细胞发育相关基因的表达量,推测cilp功能缺失可能通过抑制BMPs信号通路,影响成骨细胞分化和骨形成,从而导致了肌间骨数量的减少和脊椎骨异常融合。 相似文献
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-甲基异茨醇（2-methylisoborneol, 2-MIB）是由多种放线菌土壤生物、蓝细菌等产生的一种挥发性有机物,在水体中广泛存在。2-MIB除了导致鱼类土腥味以外,是否对鱼类造成其它影响尚不得而知。本研究将斑马鱼饲养在2-MIB浓度为42ng/L的水中24h后,进行鳃组织的转录组测序分析,发现2-MIB处理组中有163个基因显著上调,565个基因显著下调。KEGG通路富集显示氧化磷酸化相关的生化过程上调,而免疫相关信号通路发生下调, RT-qPCR进一步显示,2-MIB显著上调氧化磷酸化相关基因ndufb7、mt-cyb、mt-nd4、mt-nd6、mt-co2和mt-atp6的表达,而Toll-like receptor signaling pathway相关免疫基因rela、cd40、ikbkb、mapk8b、mapk3、ripk1l显著下调。超氧化物歧化酶SOD活性在2-MIB暴露后,鳃和肝脏组织中的SOD升高。本研究表明水体中的2-MIB会提高鱼体内活性氧水平,引起细胞损伤,还可能导致相关免疫机能下降。 相似文献
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Chamoun Z Mann RK Nellen D von Kessler DP Bellotto M Beachy PA Basler K 《Science (New York, N.Y.)》2001,293(5537):2080-2084
One of the most dominant influences in the patterning of multicellular embryos is exerted by the Hedgehog (Hh) family of secreted signaling proteins. Here, we identify a segment polarity gene in Drosophila melanogaster, skinny hedgehog (ski), and show that its product is required in Hh-expressing cells for production of appropriate signaling activity in embryos and in the imaginal precursors of adult tissues. The ski gene encodes an apparent acyltransferase, and we provide genetic and biochemical evidence that Hh proteins from ski mutant cells retain carboxyl-terminal cholesterol modification but lack amino-terminal palmitate modification. Our results suggest that ski encodes an enzyme that acts within the secretory pathway to catalyze amino-terminal palmitoylation of Hh, and further demonstrate that this lipid modification is required for the embryonic and larval patterning activities of the Hh signal. 相似文献
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Zhang L Zhou H Su Y Sun Z Zhang H Zhang L Zhang Y Ning Y Chen YG Meng A 《Science (New York, N.Y.)》2004,306(5693):114-117
Nodal proteins, members of the transforming growth factor-beta (TGFbeta) superfamily, have been identified as key endogenous mesoderm inducers in vertebrates. Precise control of Nodal signaling is essential for normal development of embryos. Here, we report that zebrafish dapper2 (dpr2) is expressed in mesoderm precursors during early embryogenesis and is positively regulated by Nodal signals. In vivo functional studies in zebrafish suggest that Dpr2 suppresses mesoderm induction activities of Nodal signaling. Dpr2 is localized in late endosomes, binds to the TGFbeta receptors ALK5 and ALK4, and accelerates lysosomal degradation of these receptors. 相似文献
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Bohn LM Lefkowitz RJ Gainetdinov RR Peppel K Caron MG Lin FT 《Science (New York, N.Y.)》1999,286(5449):2495-2498
The ability of morphine to alleviate pain is mediated through a heterotrimeric guanine nucleotide binding protein (G protein)-coupled heptahelical receptor (GPCR), the mu opioid receptor (muOR). The efficiency of GPCR signaling is tightly regulated and ultimately limited by the coordinated phosphorylation of the receptors by specific GPCR kinases and the subsequent interaction of the phosphorylated receptors with beta-arrestin 1 and beta-arrestin 2. Functional deletion of the beta-arrestin 2 gene in mice resulted in remarkable potentiation and prolongation of the analgesic effect of morphine, suggesting that muOR desensitization was impaired. These results provide evidence in vivo for the physiological importance of beta-arrestin 2 in regulating the function of a specific GPCR, the muOR. Moreover, they suggest that inhibition of beta-arrestin 2 function might lead to enhanced analgesic effectiveness of morphine and provide potential new avenues for the study and treatment of pain, narcotic tolerance, and dependence. 相似文献
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Chen W Kirkbride KC How T Nelson CD Mo J Frederick JP Wang XF Lefkowitz RJ Blobe GC 《Science (New York, N.Y.)》2003,301(5638):1394-1397
beta-Arrestins bind to activated seven transmembrane-spanning (7TMS) receptors (G protein-coupled receptors) after the receptors are phosphorylated by G protein-coupled receptor kinases (GRKs), thereby regulating their signaling and internalization. Here, we demonstrate an unexpected and analogous role of beta-arrestin 2 (betaarr2) for the single transmembrane-spanning type III transforming growth factor-beta (TGF-beta) receptor (TbetaRIII, also referred to as betaglycan). Binding of betaarr2 to TbetaRIII was also triggered by phosphorylation of the receptor on its cytoplasmic domain (likely at threonine 841). However, such phosphorylation was mediated by the type II TGF-beta receptor (TbetaRII), which is itself a kinase, rather than by a GRK. Association with betaarr2 led to internalization of both receptors and down-regulation of TGF-beta signaling. Thus, the regulatory actions of beta-arrestins are broader than previously appreciated, extending to the TGF-beta receptor family as well. 相似文献
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microRNA为短链非编码RNA,通过与靶基因3'UTR序列互补在转录后水平发挥作用。已有研究表明,microRNA在心脏发育过程中起着重要的调控作用。南极冰鱼因体内缺乏功能性血红细胞,其心脏出现了补偿性增生。前期的研究提示,独角雪冰鱼心脏中特异表达的microRNAs可能与冰鱼心脏的补偿性增生相关。本研究针对南极冰鱼心脏中高表达的miR-210-5p,运用斑马鱼显微注射、靶基因预测等手段研究了miR-210-5p对心脏发育的作用机制。结果表明:斑马鱼胚胎注射miR-210-5p后,出现心包膜水肿,心脏发育畸形等现象。qRT-PCR分析显示,过表达miR-210-5p的斑马鱼胚胎中,心脏发育相关的标志性基因bmp4、smad1、gata6以及tbx2b的表达水平下调。Western blotting分析发现,bmp/smad通路中的BMP2、BMP4、SMAD1、GATA6以及TBX2B的蛋白表达水平也显著下调。通过对tbx20基因3'UTR的靶基因生物信息学预测,以及对其进行GFP荧光表达分析,发现tbx20基因可能是miR-210-5p的一个靶基因。由此推测,miR-210-5p可能通过抑制tbx20基因的表达,并调控bmp/smad通路以抑制冰鱼心脏发育。 相似文献
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以松乳菇子实体为研究材料,采用de novo测序对松乳菇子实体进行测序与生物信息学分析,探究松乳菇子实体生长发育过程中幼菇期(LDG-1)和成熟期(LDG-2)基因表达的差异,并探寻影响松乳菇生长发育相关的主要基因和代谢通路。测序结果显示,共获得7.44G(LDG-1)和7.21G(LDG-2)的分析数据(clean reads)。KOG功能注释结果显示,松乳菇在幼菇期(LDG-1)和成熟期(LDG-2)具有全面而复杂的基因功能类别。GO富集结果提示,松乳菇在不同生长阶段(LDG-1和LDG-2)的生物代谢功能存在一定的差异。基因表达水平与聚类分析显示,ATP酶、多功能伴侣蛋白等家族基因为LDG-1和LDG-2主要高表达基因,在能量代谢与参与调控细胞周期中起重要作用。分析差异表达基因发现,相较于LDG-1期,LDG-2期有16 789个差异表达基因,其中7 635个基因上调,9 154个基因下调。差异表达基因KEGG富集通路分析结果显示,氧化磷酸化途径是松乳菇幼菇期生长发育过程中能量代谢的关键途径。进一步分析显示,MAPK信号通路是影响松乳菇子实体发育的关键信号通路,在促进松乳菇子实体进行有性生殖和调控菌丝体的极性生长中起重要作用。 相似文献