RESUMO
The vacuum ultraviolet (VUV) spectroscopy system on the Joint Texas Experimental Tokamak has been upgraded to achieve fast acquisition for the study of impurity transport in transient modulated experiments. In this upgrade, the previous high-energy charge-coupled device detector was replaced by a microchannel plate with a CsI-coated photocathode and P43 phosphor to transform the VUV light to visible light, which is then acquired by a high-speed electron-multiplying charge-coupled device. Two-stage focusing was achieved using a reference slit plate illuminated successively by a green light source and the Lyman series hydrogen spectral lines from the vacuum-conditioning plasma. The spatial resolution was evaluated as â¼4 mm based on the level of image blurring from the alignment plate. A response time of â¼2 ms was obtained with the ten-vertical-track setup.
RESUMO
Since the discovery of SUMOs (small ubiquitin-like modifiers) over 20 years ago, sumoylation has recently emerged as an important posttranslational modification involved in almost all aspects of cellular physiology. In neurons, sumoylation dynamically modulates protein function and consequently plays an important role in neuronal maturation, synapse formation and plasticity. Thus, the dysfunction of sumoylation pathway is associated with many different neurological disorders. Hundreds of different proteins implicated in the pathogenesis of neurological disorders are SUMO-modified, indicating the importance of sumoylation involved in the neurological diseases. In this review, we summarize the growing findings on protein sumoylation in neuronal function and dysfunction. It is essential to have a thorough understanding on the mechanism how sumoylation contributes to neurological diseases in developing efficient therapy for these diseases.
Assuntos
Doenças do Sistema Nervoso/genética , Neurogênese/genética , Processamento de Proteína Pós-Traducional/genética , Sumoilação/genética , Humanos , Doenças do Sistema Nervoso/fisiopatologia , Neurônios/metabolismo , Neurônios/patologia , Ubiquitina/genéticaRESUMO
Sumoylation, a post-translational modification discovered over a decade ago, turns out to be a very important regulatory mechanism mediating multiple cellular processes. Recent studies from our laboratory and others also revealed that it plays a crucial role in regulating both differentiation and pathogenesis of the ocular lens. This review will summarize these progresses.
Assuntos
Catarata/genética , Diferenciação Celular/genética , Processamento de Proteína Pós-Traducional/genética , Sumoilação/genética , Catarata/fisiopatologia , Humanos , Cristalino/patologiaRESUMO
PURPOSE: The protein phosphatase-2A (PP-2A) is one of the most important serine/threonine phosphatases in eukaryotes. The holoenzyme of PP-2A consists of three subunits: a scaffold A subunit, a catalytic C subunit and a regulatory B subunit. While both A and C subunits are coded by two different genes, the B subunits exist in 26 or more isoforms which are encoded by at least 15 different genes. Previous studies have shown that besides regulating specific PP-2A activity, various B subunits may have other functions. To explore the possible roles of the regulatory subunits of PP-2A in vertebrate development, we have cloned the gene encoding goldfish striatin, a member of the B'" family regulatory subunits for PP-2A, and determined their tissue-specific and temporal expression patterns. METHODS: The cDNA cloning was conducted with RT-PCR-based RACE. The mRNA expression levels for the goldfish striatin were analyzed with RT-PCR. The expression levels of the striatin protein from goldfish were determined with Western blot analysis. The semi-quantitation of the mRNA and protein expression levels was conducted with the software of U-scanning. RESULTS: Our study revealed that the full length cDNA for striatin consists of 2965 bp coding for a deduced protein of 769 amino acids, which bears a very high level of amino acid sequence identity with the homolog protein from other species. The striatin mRNA is highly expressed in the kidney, to a less degree in brain, fin, muscle, liver, ovary and gill, and the lowest in testis and heart. Similar pattern of protein expression is detected in the above 9 tissues. During the development of goldfish, the striatin mRNA maintains a relatively high level at the 2-cell, multiple cell and blastula stages. Then, it drops down substantially at gastrula stage and fluctuates around this level in the next 8 different stages. At the protein level, the striatin maintained higher level from 2-cell to gastrula stages, then decreased at neurula and optic vesicle stages, and gradually increased again to peak at eye pigmentation stage, then slightly decreased in the next few stages of development. CONCLUSIONS: Our results suggest that the striatin may play an important role in regulating goldfish development and adult tissue homeostasis. While the former function may or may not occur through PP- 2A functions, the later function appears to occur via PP-2A activity.
Assuntos
Proteínas de Ligação a Calmodulina/genética , Carpa Dourada/genética , Proteínas de Membrana/genética , Proteínas do Tecido Nervoso/genética , Fosfoproteínas Fosfatases/genética , Proteína Fosfatase 2/genética , Sequência de Aminoácidos/genética , Animais , Domínio Catalítico/genética , Clonagem Molecular , Regulação da Expressão Gênica no Desenvolvimento/genética , Carpa Dourada/crescimento & desenvolvimento , Humanos , Subunidades Proteicas/genética , Homologia de Sequência de AminoácidosRESUMO
CREB is an ubiquitous transcription factor regulating diverse cellular responses. Its phosphorylation at S133 is an essential event for its activation in both nervous and visual systems. The activated CREB is implicated in the regulation of development, protection, learning, memory and plasticity in the nerve system. Moreover, sumoylation, an important post-translational modification of protein, plays a key role in sustaining CREB activation in the rat hippocampus in order to enhance the long-term memory and other aspects. In the visual system, although the CREB activation by phosphorylation at S133 is similar to that as observed in the nervous system, the role of CREB sumoylation remains to be explored. This review will discuss the aspects of CREB functions and their regulation by phosphorylation and sumoylation in both systems.
Assuntos
Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Memória/fisiologia , Sumoilação/genética , Visão Ocular/genética , Animais , Regulação da Expressão Gênica , Hipocampo/crescimento & desenvolvimento , Hipocampo/fisiologia , Humanos , Fenômenos Fisiológicos do Sistema Nervoso/genética , Fosforilação/genética , Processamento de Proteína Pós-Traducional/genética , Ratos , Transdução de Sinais/genética , Visão Ocular/fisiologiaRESUMO
The male abnormal gene family contains 3 members, named mab21l1, mab21l2 and mab21l3. Since their first discovery in C. elegans, homologues of mab21l1 and mab21l2 have been found in Drosophila, Zebrafish, Xenopus, chicken, mouse and human. A number of studies have revealed that mab21 gene family members, mab21l1 and mab21l2, play important roles in regulating eye development. Here, we review the functions of the mab genes in regulating ocular development.
