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1.
Planta ; 253(1): 8, 2021 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-33387047

RESUMO

MAIN CONCLUSION: The molecular mechanism underlying white petal color in Brassica napus was revealed by transcriptomic and metabolomic analyses. Rapeseed (Brassica napus L.) is one of the most important oilseed crops worldwide, but the mechanisms underlying flower color in this crop are known less. Here, we performed metabolomic and transcriptomic analyses of the yellow-flowered rapeseed cultivar 'Zhongshuang 11' (ZS11) and the white-flowered inbred line 'White Petal' (WP). The total carotenoid contents were 1.778-fold and 1.969-fold higher in ZS11 vs. WP petals at stages S2 and S4, respectively. Our findings suggest that white petal color in WP flowers is primarily due to decreased lutein and zeaxanthin contents. Transcriptome analysis revealed 10,116 differentially expressed genes with a fourfold or greater change in expression (P-value less than 0.001) in WP vs. ZS11 petals, including 1,209 genes that were differentially expressed at four different stages and 20 genes in the carotenoid metabolism pathway. BnNCED4b, encoding a protein involved in carotenoid degradation, was expressed at abnormally high levels in WP petals, suggesting it might play a key role in white petal formation. The results of qRT-PCR were consistent with the transcriptome data. The results of this study provide important insights into the molecular mechanisms of the carotenoid metabolic pathway in rapeseed petals, and the candidate genes identified in this study provide a resource for the creation of new B. napus germplasms with different petal colors.

2.
Polymers (Basel) ; 12(2)2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-32075032

RESUMO

Herein, we report a flexible high-conductivity transparent electrode (denoted as S-PH1000), based on conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), and itsapplication to flexible semi-transparentsupercapacitors. A high conductivity of 2673 S/cm was achieved for the S-PH1000 electrode on flexible plastic substrates via a H2SO4 treatment with an optimized concentration of 80 wt.%. This is among the top electrical conductivities of PEDOT:PSS films processed on flexible substrates. As for the electrochemical properties,a high specific capacitance of 161F/g was obtained from the S-PH1000 electrode at a current density of 1 A/g. Excitingly, a specific capacitance of 121 F/g was retained even when the current density increased to 100 A/g, which demonstrates the high-rate property of this electrode. Flexible semi-transparent supercapacitors based on these electrodes demonstrate high transparency, over 60%, at 550 nm. A high power density value, over 19,200 W/kg,and energy density, over 3.40 Wh/kg, was achieved. The semi-transparent flexible supercapacitor was successfully applied topower a light-emitting diode.

3.
Biomed Res Int ; 2020: 7294820, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31998796

RESUMO

Repeated sprint cycling is an effective training method in promoting athletic performance of cyclists, which may induce severe fatigue of lower limb muscles. However, the relationship between the fatigue of each lower limb muscles and the changing of exercise performance remains unclear. In this study, ten cyclist volunteers performed a series of 6-second sprints with 24-s recovery for five times. Power, cadence, and EMG mean frequency (MNF) of each lower limb muscle group for every 2-second epoch, as well as the grey relational grade between exercise performance and MNF of each lower limb muscle group during the whole process were calculated. It has been found that MNF of Rectus femoris (RF), Vastus (VAS), Gastrocnemius (GAS), and the hamstring muscle group (HAM) showed significant negative correlation with the increase in both sprint number and intrasprint duration time, while the grey relational grade of HAM and VAS was higher than that of other muscles. The results demonstrated that the exercise performance of both power and cadence were most closing related to the fatigue degree of HAM and VAS during repeated sprint cycling exercise.


Assuntos
Ciclismo/fisiologia , Eletromiografia , Exercício Físico/fisiologia , Músculos Isquiossurais/fisiologia , Fadiga Muscular/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino
4.
Sci Total Environ ; 666: 1080-1088, 2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-30970474

RESUMO

Wetland is one of the three major ecosystems on the earth and has fundamental ecological functions and plays an irreplaceable role in serving biological survival and human development. Considering the characteristics of five types of wetlands, this study constructed a wetland ecological health evaluation indicator system using a wide variety of data from statistical report, field sampling, remote sensing, and questionnaire survey. In this study, we have selected 13 indicators (related to water, soil, biological, landscape and social factors) for ecological health evaluation of 19 wetlands in Beijing-Tianjin-Hebei region of China which have national importance. The detailed analysis shows a comprehensive health index of 5.53. There was significant spatial heterogeneity in the health status of the 19 wetlands in this region. The evaluation results and analysis provides scientific services for developing reasonable and targeted wetland protection and utilization policies of wetlands.


Assuntos
Conservação dos Recursos Naturais/métodos , Monitoramento Ambiental/métodos , Tecnologia de Sensoriamento Remoto , Áreas Alagadas , Pequim
5.
Int J Mol Sci ; 19(8)2018 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-30049941

RESUMO

Brassica plants exhibit both high biomass productivity and high rates of heavy metal absorption. Metallothionein (MT) proteins are low molecular weight, cysteine-rich, metal-binding proteins that play crucial roles in protecting plants from heavy metal toxicity. However, to date, MT proteins have not been systematically characterized in Brassica. In this study, we identified 60 MTs from Arabidopsis thaliana and five Brassica species. All the MT family genes from Brassica are closely related to Arabidopsis MTs, encoding putative proteins that share similar functions within the same clades. Genome mapping analysis revealed high levels of synteny throughout the genome due to whole genome duplication and segmental duplication events. We analyzed the expression levels of 16 Brassica napus MTs (BnaMTs) by RNA-sequencing and real-time RT-PCR (RT-qPCR) analysis in plants under As3+ stress. These genes exhibited different expression patterns in various tissues. Our results suggest that BnaMT3C plays a key role in the response to As3+ stress in B. napus. This study provides insight into the phylogeny, origin, and evolution of MT family members in Brassica, laying the foundation for further studies of the roles of MT proteins in these important crops.


Assuntos
Arsênico/metabolismo , Brassica napus/genética , Regulação da Expressão Gênica de Plantas , Metalotioneína/genética , Proteínas de Plantas/genética , Sequência de Aminoácidos , Brassica napus/química , Brassica napus/metabolismo , Genoma de Planta , Metalotioneína/química , Metalotioneína/metabolismo , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Alinhamento de Sequência , Estresse Fisiológico , Transcriptoma
6.
Biomed Res Int ; 2018: 9341215, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29850588

RESUMO

The increased popularization of cycling has brought an increase in cycling-related injuries, which has been suggested to be associated with muscle fatigue. However, it still remains unclear on the utility of different EMG indices in muscle fatigue evaluation induced by cycling exercise. In this study, ten cyclist volunteers performed a 30-second all-out cycling exercise after a warm-up period. Surface electromyography (sEMG) from vastus lateralis muscle (VL) and power output and cadence were recorded and EMG RMS, MF and MPF based on Fourier Transform, MDF and MNF based on wavelet packet transformation, and C(n) based on Lempel-Ziv complexity algorithm were calculated. Utility of the indices was compared based on the grey rational grade of sEMG indices and power output and cadence. The results suggested that MNF derived from wavelet packet transformation was significantly higher than other EMG indices, indicating the potential application for fatigue evaluation induced by all-out cycling exercise.


Assuntos
Algoritmos , Ciclismo , Eletromiografia , Exercício Físico/fisiologia , Fadiga Muscular/fisiologia , Feminino , Humanos , Masculino , Processamento de Sinais Assistido por Computador , Adulto Jovem
7.
Materials (Basel) ; 12(1)2018 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-30602696

RESUMO

The effect of recrystallization annealing on corrosion behavior of Ta-4%W alloy was studied. It is found that the deformed sample contains high dense dislocations and dislocation boundaries. During annealing, these dislocations and dislocation boundaries are replaced by recrystallizing grains until the alloy is fully recrystallized. Both the anodic dissolution and the cathodic activity is much more blocked. The corrosion potential gradual shift towards negative values and corrosion current density decrease, while polarization resistance increases after annealing, indicating enhanced corrosion resistance of the alloy. Such an enhancement is caused by the increase of low-Σ coincide site lattice boundaries and decrease of dislocations and dislocation boundaries.

8.
Genes (Basel) ; 8(10)2017 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-29064393

RESUMO

The basic region/leucine zipper motif (bZIP) transcription factor family is one of the largest families of transcriptional regulators in plants. bZIP genes have been systematically characterized in some plants, but not in rapeseed (Brassica napus). In this study, we identified 247 BnbZIP genes in the rapeseed genome, which we classified into 10 subfamilies based on phylogenetic analysis of their deduced protein sequences. The BnbZIP genes were grouped into functional clades with Arabidopsis genes with similar putative functions, indicating functional conservation. Genome mapping analysis revealed that the BnbZIPs are distributed unevenly across all 19 chromosomes, and that some of these genes arose through whole-genome duplication and dispersed duplication events. All expression profiles of 247 bZIP genes were extracted from RNA-sequencing data obtained from 17 different B. napus ZS11 tissues with 42 various developmental stages. These genes exhibited different expression patterns in various tissues, revealing that these genes are differentially regulated. Our results provide a valuable foundation for functional dissection of the different BnbZIP homologs in B. napus and its parental lines and for molecular breeding studies of bZIP genes in B. napus.

9.
Macromol Rapid Commun ; 38(17)2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28691381

RESUMO

Gelation-mediated phase separation is applied to prepare immiscible polymer bilayer films with an interlocking interface structure. Polymer systems consisting of copolymer of urea and polydimethylsiloxane and epoxy are selected to demonstrate the feasibility. When the epoxy fraction exceeds 25 wt%, well-defined bilayer structures self-form by a one-pot casting method in which the phase separation state is fixed by an evaporation-induced gelation. Microscopy studies of the resulting bilayers clearly reveal that interlocking structures form during the bilayer films construct. The interlocking structures lead to an enhanced interfacial adhesion and higher fracture energy. The current strategy might offer a facile way to in situ create an interlocking interface between immiscible polymer systems.


Assuntos
Técnicas de Química Analítica/instrumentação , Polímeros/síntese química , Dimetilpolisiloxanos/química , Géis , Ureia/química
10.
Dev Cell ; 39(4): 438-451, 2016 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-27746045

RESUMO

Hedgehog (Hh) signaling plays a central role in development and diseases. Hh activates its signal transducer and GPCR-family protein Smoothened (Smo) by inducing Smo phosphorylation, but whether Smo is activated through other post-translational modifications remains unexplored. Here we show that sumoylation acts in parallel with phosphorylation to promote Smo cell-surface expression and Hh signaling. We find that Hh stimulates Smo sumoylation by dissociating it from a desumoylation enzyme Ulp1. Sumoylation of Smo in turn recruits a deubiquitinase UBPY/USP8 to antagonize Smo ubiquitination and degradation, leading to its cell-surface accumulation and elevated Hh pathway activity. We also provide evidence that Shh stimulates sumoylation of mammalian Smo (mSmo) and that sumoylation promotes ciliary localization of mSmo and Shh pathway activity. Our findings reveal a conserved mechanism whereby the SUMO pathway promotes Hh signaling by regulating Smo subcellular localization and shed light on how sumoylation regulates membrane protein trafficking.


Assuntos
Proteínas de Drosophila/metabolismo , Proteínas Hedgehog/metabolismo , Transdução de Sinais , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Receptor Smoothened/metabolismo , Animais , Cílios/metabolismo , Drosophila melanogaster/metabolismo , Regulação da Expressão Gênica , Lisina/metabolismo , Mamíferos/metabolismo , Fosforilação , Sumoilação , Ubiquitinação , Asas de Animais/metabolismo
11.
Angew Chem Int Ed Engl ; 55(3): 979-82, 2016 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-26630234

RESUMO

Thick, uniform, easily processed, highly conductive polymer films are desirable as electrodes for solar cells as well as polymer capacitors. Here, a novel scalable strategy is developed to prepare highly conductive thick poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (HCT-PEDOT:PSS) films with layered structure that display a conductivity of 1400 S cm(-1) and a low sheet resistance of 0.59 ohm sq(-1). Organic solar cells with laminated HCT-PEDOT:PSS exhibit a performance comparable to the reference devices with vacuum-deposited Ag top electrodes. More importantly, the HCT-PEDOT:PSS film delivers a specific capacitance of 120 F g(-1) at a current density of 0.4 A g(-1). All-solid-state flexible symmetric supercapacitors with the HCT-PEDOT:PSS films display a high volumetric energy density of 6.80 mWh cm(-3) at a power density of 100 mW cm(-3) and 3.15 mWh cm(-3) at a very high power density of 16160 mW cm(-3) that outperforms previous reported solid-state supercapacitors based on PEDOT materials.

12.
Chem Commun (Camb) ; 50(91): 14209-12, 2014 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-25285341

RESUMO

A Li3N protection layer is fabricated on the surface of a Li anode by an in situ method to suppress the shuttle effect on the basis of anode protection. The discharge capacity is retained at 773 mA h g(-1) after 500 cycles with an average coulombic efficiency of 92.3% in the electrolyte without LiNO3, while the sulfur loading of the simple sulfur cathode was 2.5-3 mg cm(-2).

13.
Phys Chem Chem Phys ; 16(39): 21225-9, 2014 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-25198434

RESUMO

A room temperature hybrid electrolyte based lithium-sulfur cell was successfully cycled with an excellent coulombic efficiency of 100%. The initial discharge specific capacities of up to 1528 mA h g(-1), 1386 mA h g(-1) and 1341 mA h g(-1), respectively, at C/20, C/5 and C/2 rates were realized and remained at 720 mA h g(-1) after 40 cycles at the C/5 rate.

14.
Sci Signal ; 7(332): ra62, 2014 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-24985345

RESUMO

Hedgehog (Hh) is a secreted glycoprotein that binds its receptor Patched to activate the G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor-like protein Smoothened (Smo). In Drosophila, protein kinase A (PKA) phosphorylates and activates Smo in cells stimulated with Hh. In unstimulated cells, PKA phosphorylates and inhibits the transcription factor Cubitus interruptus (Ci). We found that in cells exposed to Hh, the catalytic subunit of PKA (PKAc) bound to the juxtamembrane region of the carboxyl terminus of Smo. PKA-mediated phosphorylation of Smo further enhanced its association with PKAc to form stable kinase-substrate complexes that promoted the PKA-mediated transphosphorylation of Smo dimers. We identified multiple basic residues in the carboxyl terminus of Smo that were required for interaction with PKAc, Smo phosphorylation, and Hh pathway activation. Hh induced a switch from the association of PKAc with a cytosolic complex of Ci and the kinesin-like protein Costal2 (Cos2) to a membrane-bound Smo-Cos2 complex. Thus, our study uncovers a previously uncharacterized mechanism for regulation of PKA activity and demonstrates that the signal-regulated formation of kinase-substrate complexes plays a central role in Hh signal transduction.


Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Proteínas de Drosophila/metabolismo , Proteínas Hedgehog/metabolismo , Receptores Acoplados a Proteínas-G/metabolismo , Transdução de Sinais/fisiologia , Animais , Proteínas Quinases Dependentes de AMP Cíclico/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/genética , Drosophila melanogaster , Proteínas Hedgehog/genética , Fosforilação/fisiologia , Multimerização Proteica/fisiologia , Receptores Acoplados a Proteínas-G/genética , Receptor Smoothened , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
15.
J Nanosci Nanotechnol ; 14(9): 7181-8, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25924388

RESUMO

To study the effect of calcination temperatures on the sulfur recovery catalysts, titanium oxide (TiO2), as sulfur recovery catalysts, were treated at four calcination temperatures of 300 degrees C, 500 degrees C, 700 degrees C and 900 degrees C. The structure of the catalysts were characterized by X-ray powder diffraction (XRD), Raman, transmission electron microscopy (TEM), Scanning electron microscopy (SEM), temperature thermogravimetry (TG) and differential scanning calorimetry (DSC). The results showed that with the calcination temperature increasing, the particle size of the TiO2 catalysts increases but the surface area and total pore volume decrease. The extent of reduction was more serious after calcination at 500 degrees C. Rutile phase were formed at calcination temperature about 700 degrees C. On the basis of these results, a scheme for the change of TiO2 with increasing calcination temperatures was proposed. The Claus catalytic activity of the TiO2 catalysts was evaluated in the traditional conditions. It was found that the Claus catalytic activity, which decreased a little when the calcination temperature was no more than 500 degrees C but much once the calcination temperature was more than 500 degrees C, was not only related to the surface area and pore volume, but also the phase of the TiO2. The activity of rutile was less than the anatase and a possible reaction pathway to reveal this mechanism was proposed.

16.
Mol Biol Rep ; 39(4): 4249-59, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21786157

RESUMO

The complete mitochondrial genome of the spinyhead croaker Collichthys lucidus was determined using long-PCR and primer walking methods. It is a circular molecule of 16,451 bp in length with a standard set of 22 tRNAs, 2 rRNAs, 13 protein-coding genes as well as a non-coding control region in the same order as those of the other bony fishes. C. lucidus mitogenome exhibited a clear strand-specific bias in nucleotide composition, as evidence by a GC- skew of the H-strand of -0.319. The strand-specific bias was also reflected in the codon usage of genes oriented in opposite directions. All tRNA genes except for tRNA( Ser(AGY)) harbored the typical cloverleaf secondary structures and possessed anticodons that matched the vertebrate mitochondrial genetic code. Contrary to the typical structure of control region consistig of TAS, central, and CSB domains, there were no central conserved blocks available in C. lucidus mitogenome. Despite extensive studies based on both morphology and molecules, phylogenetic position of C. lucidus with Sciaenidae is still controversial. Our phylogenetic results provided more evidence to support previous morphological studies and consistently placed C. lucidus as a sister taxon to Collichthys niveatus, with both of these taxa forming the monophyletic Collichthys.


Assuntos
Genoma Mitocondrial/genética , Perciformes/genética , Filogenia , Animais , Composição de Bases/genética , Sequência de Bases , Códon/genética , DNA Intergênico/genética , DNA Mitocondrial/genética , Dados de Sequência Molecular , Nucleotídeos/genética , Fases de Leitura Aberta/genética , RNA Ribossômico/genética , RNA de Transferência/genética , Análise de Sequência de DNA
17.
Gene ; 491(2): 210-23, 2012 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-21989484

RESUMO

The monophyly and phylogenetic relationships of Pseudosciaeniae have long been controversial. Here we describe the mitochondrial genome (mitogenome) sequence of Collichthys niveatus. It is a circular double-stranded DNA molecule of 16,450 base pairs (bp) in length with a standard set of 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs), 13 protein-coding genes as well as a non-coding control region. The mitogenome of C. niveatus shared common features with those of other bony fishes in terms of gene arrangement, base composition, and tRNA structures. The C. niveatus mitogenome exhibited pronounced strand-specific asymmetry in nucleotide composition, which was also reflected in the codon usage of genes oriented in opposite directions. Contrary to the typical structure of the control region, the central conserved blocks (CSB-D, -E, and -F) could not be detected in C. niveatus mitogenome. Phylogenetic analysis based on whole mitogenome sequences provided strong support for the monophyly of Pseudosciaeniae, and sister-group relationships of C. niveatus+Collichthys lucidus and Larimichthys crocea+Larimichthys polyactis, which was consistent with the traditional taxonomy. Unexpected divergence was found in two C. niveatus mitogenomes and several hypotheses were proposed to explain this observation including misidentification and introgressive hybridization between C. niveatus and L. polyactis, and polyphyletic origin of C. niveatus. We considered species misidentification to be the main hypothesis. However, additional data is essential to test these proposed hypotheses.


Assuntos
Genoma Mitocondrial , Perciformes/genética , Animais , Sequência de Bases , Códon , DNA , DNA Circular , Filogenia , Alinhamento de Sequência , Análise de Sequência
18.
PLoS Biol ; 9(6): e1001083, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21695114

RESUMO

Hedgehog (Hh) signaling regulates embryonic development and adult tissue homeostasis through the GPCR-like protein Smoothened (Smo), but how vertebrate Smo is activated remains poorly understood. In Drosophila, Hh dependent phosphorylation activates Smo. Whether this is also the case in vertebrates is unclear, owing to the marked sequence divergence between vertebrate and Drosophila Smo (dSmo) and the involvement of primary cilia in vertebrate Hh signaling. Here we demonstrate that mammalian Smo (mSmo) is activated through multi-site phosphorylation of its carboxyl-terminal tail by CK1α and GRK2. Phosphorylation of mSmo induces its active conformation and simultaneously promotes its ciliary accumulation. We demonstrate that graded Hh signals induce increasing levels of mSmo phosphorylation that fine-tune its ciliary localization, conformation, and activity. We show that mSmo phosphorylation is induced by its agonists and oncogenic mutations but is blocked by its antagonist cyclopamine, and efficient mSmo phosphorylation depends on the kinesin-II ciliary motor. Furthermore, we provide evidence that Hh signaling recruits CK1α to initiate mSmo phosphorylation, and phosphorylation further increases the binding of CK1α and GRK2 to mSmo, forming a positive feedback loop that amplifies and/or sustains mSmo phosphorylation. Hence, despite divergence in their primary sequences and their subcellular trafficking, mSmo and dSmo employ analogous mechanisms for their activation.


Assuntos
Caseína Quinase Ialfa/metabolismo , Quinase 2 de Receptor Acoplado a Proteína G/metabolismo , Proteínas Hedgehog/metabolismo , Receptores Acoplados a Proteínas-G/metabolismo , Animais , Membrana Celular/metabolismo , Células Cultivadas , Cílios/metabolismo , Drosophila/genética , Drosophila/metabolismo , Camundongos , Células NIH 3T3 , Fosforilação , Transdução de Sinais , Receptor Smoothened , Transfecção
19.
Prog Neurobiol ; 90(2): 276-83, 2010 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-19853638

RESUMO

There are two major secretory pathways in neurons, the regulated pathway and the constitutive pathway. Neuropeptides and other regulated secretory proteins are known to be sorted into large dense-core vesicles of the regulated pathway in the trans-Golgi network and are secreted upon stimulus-induced increases in intracellular Ca(2+). The newly synthesized cell surface receptors are usually sorted into microvesicles of the constitutive pathway and inserted into the plasma membrane by spontaneous exocytosis. Small-diameter sensory neurons in dorsal root ganglia and pheochromocytoma cells express neuropeptides (e.g., substance P) and several neuropeptide receptors including opioid receptors. The mu-opioid receptors are delivered to the cell surface through the constitutive pathway, whereas another type of opioid receptor, the delta-opioid receptor, is often found in the membrane of large dense-core vesicles and can be inserted into the plasma membrane when exocytosis occurs. Recent studies show that sequences with opposite electrical polarity within the prohormones of substance P are essential for their sorting into large dense-core vesicles. Moreover, the delta-opioid receptor is sorted into large dense-core vesicles by its interaction with protachykinin, a prohormone of substance P. These findings provide insight into the molecular mechanisms that determine the sorting and trafficking of neuropeptides and neuropeptide receptors in neurons.


Assuntos
Neurônios/metabolismo , Neuropeptídeos/metabolismo , Receptores de Neuropeptídeos/metabolismo , Via Secretória/fisiologia , Animais , Cálcio/metabolismo , Humanos , Neurônios/ultraestrutura , Transporte Proteico , Receptores de Neuropeptídeos/ultraestrutura , Vesículas Secretórias/metabolismo , Vesículas Secretórias/ultraestrutura , Rede trans-Golgi/metabolismo , Rede trans-Golgi/ultraestrutura
20.
Traffic ; 9(12): 2165-79, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18939957

RESUMO

The sorting of neuropeptide tachykinins into large dense-core vesicles (LDCVs) is a key step in their regulated secretion from neurons. However, the sorting mechanism for protachykinin has not yet to be clearly resolved. In this study, we report that the clustered short elements with charged amino acids regulate the efficiency of protachykinin sorting into LDCVs. A truncation experiment showed that the propeptide and the mature peptide-containing sequence of protachykinin were sorted into LDCVs. These two regions exhibit a polarized distribution of charged amino acids. The LDCV localization of the propeptide was gradually decreased with an increasing number of neutral amino acids. Furthermore, the short element with four to five amino acids containing two charged residues was found to be a basic unit for LDCV sorting that enables regulated secretion. In the native propeptide sequence, these charged short elements were clustered to enhance the intermolecular aggregation by electrostatic interaction and produce a gradual and additive effect on LDCV sorting. The optimal conditions for intermolecular aggregation of protachykinin were at millimolar Ca(2+) concentrations and pH 5.5-6.0. These results demonstrate that the charged short elements are clustered such that they serve as aggregative signals and regulate the efficiency of protachykinin sorting into LDCVs. These findings reveal a novel mechanism for the sorting of neuropeptides into a regulated secretory pathway.


Assuntos
Aminoácidos/metabolismo , Elétrons , Precursores de Proteínas/metabolismo , Vesículas Secretórias/metabolismo , Taquicininas/metabolismo , Sequência de Aminoácidos , Aminoácidos/química , Animais , Cálcio/metabolismo , Concentração de Íons de Hidrogênio , Microscopia Imunoeletrônica , Dados de Sequência Molecular , Células PC12 , Peptídeos/metabolismo , Precursores de Proteínas/química , Ratos , Vesículas Secretórias/ultraestrutura , Taquicininas/química
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