Prediction of Golgi Type II membrane proteins based on their transmembrane domains

Motivation: A major issue in cell biology today is how distinct intracellular regions of the cell, like the Golgi Apparatus, maintain their unique composition of proteins and lipids. The cell differentially separates Golgi resident proteins from proteins that move through the organelle to other subcellular destinations. We set out to determine if we could distinguish these two types of transmembrane proteins using computational approaches. Results: A new method has been developed to predict Golgi membrane proteins based on their transmembrane domains. To establish the prediction procedure, we took the hydrophobicity values and frequencies of different residues within the transmembrane domains into consideration. A simple linear discriminant function was developed with a small number of parameters derived from a dataset of Type II transmembrane proteins of known localization. This can discriminate between proteins destined for Golgi apparatus or other locations (post-Golgi) with a success rate of 89.3% or 85.2%, respectively on our redundancy-reduced data sets.

Anomalies in the developing neural and visceral head skeleton of the Australian lungfish, Neoceratodus forsteri

Several anomalies occur in the developing neural and visceral head skeleton of young specimens of Neoceratodus forsteri that have been reared under laboratory conditions. These include anomalies of the basicranium and its derivatives, aberrations of the anterior mandible and hyoid apparatus, and abnormalities in the articulation of the jaws and the elements that produce them. Apart from the occasional absence of the basihyal, and failure of the quadrate processes to form, the anomalies are not deficiencies. Most involve malformations of parts of the neurocranium and visceral skeleton, inappropriate articulations or fusions between elements, disunity in structures that are normally fused and the appearance of supernumerary elements. The incidence of chondral anomalies, generally higher than aberrations that occur in the dermal skeleton in juvenile lungfish, ranges from 1-10% in laboratory reared individuals that have not been subjected to experimental interference. The anomalies differ from those found in many amphibian populations, in the field and in the laboratory, because they involve the cranium, and not the limbs, and the lungfish have not been exposed to the factors that cause anomalies in the amphibians. It is unlikely that the existence of those anomalies, if it is reflected in the wild population, places a selective pressure on the lungfish, because, in a normal season, less than 1% of the total number of eggs produced survive to be recruited into the adult population.

Numerical investigation of turbulent flow around a rotating stepped cylinder for corrosion study

Direct numerical simulation has been carried out for turbulent flow set up by a rotating cylinder with two backward-facing steps axisymmetrically mounted in the circumferential direction. This flow geometry creates a qualitatively similar flow pattern as observed near, a sudden, pipe expansion or a plane backward-facing step, characterized by flow separation and reattachment. A region of intense turbulence intensity and high wall-shear-stress fluctuations is formed in,the recirculating I region downstream of the step, where high mass-transfer capacity was also experimentally observed. Since, corrosion is frequently mass-transfer., controlled, our findings, put forward this apparatus as useful tool for future corrosion research.

Intracellular sorting and transport of proteins

The secretory and endocytic pathways of eukaryotic organelles consist of multiple compartments, each with a unique set of proteins and lipids. Specific transport mechanisms are required to direct molecules to defined locations and to ensure that the identity, and hence function, of individual compartments are maintained. The localisation of proteins to specific membranes is complex and involves multiple interactions. The recent dramatic advances in understanding the molecular mechanisms of membrane transport has been due to the application of a multi-disciplinary approach, intergrating membrane biology, genetics, imaging, protein and lipid biochemistry and structural biology. The aim of this review is to summarise the general principles of protein sorting in the secretory and endocytic pathways and to highlight the dynamic nature of these processes. The molecular mechanisms involved in this transport along the secretory and endocytic pathways are discussed along with the signals responsible for targeting proteins to different intracellular locations. (C) 2003 Elsevier Science Ltd. All rights reserved.

Localization of the Epstein-Barr virus protein LMP 1 to exosomes

The Epstein-Barr virus latent membrane protein (LMP 1) functions as a constitutively active signalling molecule and associates in lipid rafts clustered with other signalling molecules. Using immunofluorescent confocal microscopy, LMP 1 was shown to have an heterogeneous distribution among individual cells which was not related to the cell cycle stage. LMP 1 was shown to localize to intracellular compartments in cells other than the plasma membrane, Co-labelling of cells with both an LIMP 1 antibody and an antibody to the Golgi protein GS15 revealed that the intracellular LMP 1 partly co-localized with the Golgi apparatus. Further confirmation of intracellular LMP 1 localization was obtained by immunoelectron microscopy with rabbit polyclonal LIMP 1 antibodies and cryosectioning. As well as being present in intracellular foci, LMP 1 co-localized in part with MHC-II and was present on exosomes derived from a lymphoblastoid cell line. Preparations of LMP 1 containing exosomes were shown to inhibit the proliferation of peripheral blood mononuclear cells, suggesting that LIMP 1 could be involved in immune regulation. This may be of particular relevance in EBV-associated tumours such as nasopharyngeal carcinoma and Hodgkin's disease, as LMP 1-containing exosomes may be taken up by infiltrating T-lymphocytes, where LMP 1 could exert an anti-proliferative effect, allowing the tumour cells to evade the immune system.

The trans-membrane protein p25 forms highly specialized domains that regulate membrane composition and dynamics

Trans-membrane proteins of the p24 family are abundant, oligomeric proteins predominantly found in cis-Golgi membranes. They are not easily studied in vivo and their functions are controversial. We found that p25 can be targeted to the plasma membrane after inactivation of its canonical KKXX motif (KK to SS, p25SS), and that p25SS causes the co-transport of other p24 proteins beyond the Golgi complex, indicating that wild-type p25 plays a crucial role in retaining p24 proteins in cis-Golgi membranes. We then made use of these observations to study the intrinsic properties of these proteins, when present in a different membrane context. At the cell surface, the p25SS mutant segregates away from both the transferrin receptor and markers of lipid rafts, which are enriched in cholesterol and glycosphingolipids. This suggests that p25SS localizes to, or contributes to form, specialized membrane domains, presumably corresponding to oligomers of p25SS and other p24 proteins. Once at the cell surface, p25SS is endocytosed, together with other p24 proteins, and eventually accumulates in late endosomes, where it remains confined to well-defined membrane regions visible by electron microscopy. We find that this p25SS accumulation causes a concomitant accumulation of cholesterol in late endosomes, and an inhibition of their motility - two processes that are functionally linked. Yet, the p25SS-rich regions themselves seem to-exclude not only Lamp1 but also accumulated cholesterol. One may envision that p25SS accumulation, by excluding cholesterol from oligomers, eventually overloads neighboring late endosomal membranes with cholesterol beyond their capacity (see Discussion). In any case, our data show that p25 and presumably other p24 proteins are endowed with the intrinsic capacity to form highly specialized domains that control membrane composition and dynamics. We propose that p25 and other p24 proteins control the fidelity of membrane transport by maintaining cholesterol-poor membranes in the Golgi complex.

Narrating the guillotine: Punishment technology as myth and symbol

The work of Michel Foucault sees modern penal technology its ann expression of power that operates through and is motivated by a dry instrumental reason. This article draws upon Durkheim and Bakhtin to advance a radically alternative approach. It is suggested that such technology is invested with sacred and profane symbolism and is understood via emotionally charged, dramatically compelling narrative frames. Tensions between official and unauthorized discourses can be understood through a center/periphery model of culture. In an extended case study of the guillotine, it is shown dial the apparatus was initially legitimated as an expression of a sacred revolutionary code. Such a discourse was subsequently destabilized by popular medical debates that raised the specter of pain after decapitation. While inconclusive, these new motifs mobilized Gothic and grotesque themes that confronted the rationalist aesthetics of the guillotine. A situation of Bakhtinian hetoroglossia eventuated. Uncertainty, the uncanny and fable entered a discursive field of increasing complexity.

GRIP domain-mediated targeting of two new coiled-coil proteins, GCC88 and GCC185, to subcompartments of the trans-Golgi network

The GRIP domain is a targeting sequence found in a family of coiled-coil peripheral Golgi proteins. Previously we demonstrated that the GRIP domain of p230/golgin245 is specifically recruited to tubulovesicular structures of the traps-Golgi network (TGN). Here we have characterized two novel Golgi proteins with functional GRIP domains, designated GCC88 and GCC185. GCC88 cDNA encodes a protein of 88 kDa, and GCC185 cDNA encodes a protein of 185 kDa. Both molecules are brefeldin A-sensitive peripheral membrane proteins and are predicted to have extensive coiled-coil regions with the GRIP domain at the C terminus. By immunofluorescence and immunoelectron microscopy GCC88 and GCC185, and the GRIP protein golgin97, are all localized to the TGN of Hela cells. Overexpression of full-length GCC88 leads to the formation of large electron dense structures that extend from the traps-Golgi. These de novo structures contain GCC88 and co-stain for the TGN markers syntaxin 6 and TGN38 but not for alpha2,6-sialyltransferase, beta-COP, or cis-Golgi GM130. The formation of these abnormal structures requires the N-terminal domain of GCC88. TGN38, which recycles between the TGN and plasma membrane, was transported into and out of the GCC88 decorated structures. These data introduce two new GRIP domain proteins and implicate a role for GCC88 in the organization of a specific TGN subcompartment involved with membrane transport.

Carreiras p??blicas em uma ordem democr??tica: entre os modelos burocr??tico e gerencial

Refletindo sobre modelo de carreira mais adequado para a Administra????o P??blica nesta era de economia globalizada e de maiores exig??ncias de efici??ncia e flexibilidade na gest??o dos aparatos governamentais, questiona-se aqui a id??ia de que o modelo burocr??tico deva ser substitu??do pelo modelo gerencial. Considerando essa id??ia apenas parcialmente verdadeira, nossa argumenta????o vai na seguinte dire????o: como a burocracia ?? a forma espec??fica de organiza????o do aparato administrativo do Estado de Direito, este modelo n??o pode ser rejeitado, sob pena de comprometimento desse Estado. Mas ele precisa ser flexibilizado, superando e reduzindo o formalismo excessivo e a rigidez que sua realiza????o hist??rica possa ter gerado nos diferentes pa??ses. Igualmente, deve ser aperfei??oado em seus mecanismos de controle, at?? como condi????o para sua manuten????o eficaz nos governos democr??ticos contempor??neos.

O t??nel no fim da luz: a privatiza????o do setor el??trico em Mato Grosso

Este artigo tem por objetivo analisar a forma????o de consensos sociais e pol??ticos para a reforma do Estado e de seu aparelho em n??vel estadual, conforme a governabilidade democr??tica. Optou-se por uma pesquisa sobre a privatiza????o das Centrais El??tricas Mato- Grossenses S.A. (Cemat), considerada representativa tanto da reforma empreendida pelo Estado de Mato Grosso quanto das dificuldades do setor el??trico em n??vel nacional. O referencial metodol??gico dessa pesquisa ?? composto de um problema e de quatro hip??teses de trabalho. Trata-se de estudo de caso da esp??cie ???provas de plausibilidade???, em que, por uma aplica????o iterativa, apresenta-se uma proposi????o te??rica inicial e, em seguida, as conclus??es da pesquisa s??o comparadas, o que permite sua revis??o e compara????o. Para tanto, descrevem-se a privatiza????o da Cemat e os problemas da desestatiza????o do setor el??trico brasileiro no seu conjunto. Por fim, na conclus??o, verifica-se a validade das hip??teses e fazem-se algumas considera????es finais sobre a pesquisa.

Uma reforma gerencial da administra????o p??blica no Brasil

O texto aborda as principais caracter??sticas da reforma administrativa em andamento no Brasil. A proposta ?? de mudan??a da administra????o p??blica burocr??tica e clientelista para uma administra????o p??blica gerencial, baseada no enfoque da ???nova administra????o p??blica???. A reforma brasileira distingue as atividades exclusivas do Estado, detentoras do poder de Estado, dos servi??os sociais e cient??ficos e das empresas estatais. O primeiro setor permanecer?? dentro do aparato estatal e as empresas estatais est??o sendo privatizadas. Com rela????o aos servi??os sociais e cient??ficos, que recebem um suporte substancial do Estado, a proposta ?? de transform??-los em organiza????es sociais n??o lucrativas, seguindo as linhas dos ???quangos??? (quasi non governamental organizations) ingleses.

A pol??tica da reforma do Estado: um exame de abordagens te??ricas

O artigo aborda a contribui????o de tr??s diferentes perspectivas te??ricas ??? o institucionalismo da economia pol??tica (IEP), o institucionalismo da escolha racional (IER) e o institucionalismo da sociologia (IS) ??? para a compreens??o dos desdobramentos da organiza????o estatal e das pol??ticas de reforma do aparelho do Estado. Tais perspectivas s??o complementares ou excludentes, mas cada uma oferece explica????es diferentes sobre atores, prefer??ncias e dificuldades a serem enfrentadas. O texto explica algumas das hip??teses sobre reforma do Estado, contidas em cada perspectiva, observando as suas vantagens e limita????es, e fornece tamb??m uma avalia????o preliminar da relev??ncia te??rica de cada uma para a pesquisa emp??rica na Am??rica Latina e Europa Oriental.

Novas tend??ncias do mercado de trabalho

Na ruptura social fordista, o desemprego cresce bruscamente, fazendo surgir configura????es vari??veis, onde o conceito de press??o salarial passa a designar o complemento monet??rio indireto, destinado a assegurar a reprodu????o intergeneracional nas sociedades capitalistas plenamente desenvolvidas. A nova rela????o salarial compreende a rela????o de emprego (rela????o monet??ria direta) e a press??o salarial (rela????o monet??ria indireta). O aparecimento de rela????es de trabalho prec??rias for??a a press??o salarial a substituir a prote????o social em decad??ncia. Dos arranjos em forma????o, impor-se-??o os que encontrarem uma coer??ncia sist??mica m??nima. O poder p??blico agir?? como regulador da rela????o salarial e garantidor ??ltimo da press??o salarial, respeitando a flexibilidade do aparelho produtivo e a mobilidade e flexibilidade do trabalho. O autor tra??a trajet??rias nacionais baseados em 2 cen??rios estilizados, que s??o a variante americana (modelo t??pico da desregulamenta????o e flexibilidade externa) e a variante europ??ia (modelo t??pico da gest??o institucionalizada e flexibilidade interna).

Fundamentos para uma pol??tica de carreiras no contexto da reforma gerencial

Com o advento da administra????o gerencial no ??mbito do aparelho do Estado, em complementa????o ?? administra????o burocr??tica, verifica-se certa turbul??ncia na gest??o de pessoal na administra????o p??blica, decorrente da s??bita aus??ncia de fundamentos conceituais s??lidos que permitam pensar a administra????o do capital humano do Estado em um contexto de transforma????o. Este artigo procura estabelecer as bases para a recupera????o destes fundamentos, propondo tr??s crit??rios de design de carreiras: a estrutura de incentivos, os mecanismos de governan??a e a gest??o do conhecimento. Em seguida, exemplifica-se a utiliza????o destes crit??rios pela an??lise de seis temas pr??prios ?? discuss??o sobre carreiras no servi??o p??blico: remunera????o, sele????o, recrutamento e desenvolvimento, mobilidade, promo????o, carreiras para ag??ncias executivas e controle social da burocracia.

A reforma do Estado no contexto latino-americano: coment??rios sobre alguns impasses e poss??veis desdobramentos

O artigo se constitui em uma reflex??o sobre a reforma do Estado nos pa??ses latinoamericanos, em especial no que se refere a seu aparato institucional ??? a "m??quina administrativa". Identificadas como reformas de 2a gera????o (as de 1a s??o as do reajuste macroecon??mico), o conjunto dos esfor??os modernizadores busca a regenera????o das institui????es p??blicas duramente afetadas pela crise econ??mico-financeira dos anos 80, e/ou at?? mesmo a cria????o de novas institui????es, visando a constru????o de um Estado forte, apoiado em uma economia din??mica e competitiva, da qual ?? parceiro e regulador, al??m de desempenhar de forma adequada suas fun????es cl??ssicas. O autor discute as quest??es institucionais e sociais (accountability, governance, conex??es entre as reformas econ??mico-financeiras), a mudan??a de paradigma do papel do Estado e os desafios a serem enfrentados.