scholarly journals Role of the PAS1 gene of Pichia pastoris in peroxisome biogenesis.

1994 ◽  
Vol 127 (5) ◽  
pp. 1259-1273 ◽  
Author(s):  
J A Heyman ◽  
E Monosov ◽  
S Subramani
Keyword(s):  
Pichia Pastoris ◽  
Biochemical Analysis ◽  
Sequence Similarity ◽  
Carbon Sources ◽  
Peroxisome Biogenesis ◽  
Daughter Cells ◽  
New Information ◽  
Membrane Bound ◽  
High Level

Several groups have reported the cloning and sequencing of genes involved in the biogenesis of yeast peroxisomes. Yeast strains bearing mutations in these genes are unable to grow on carbon sources whose metabolism requires peroxisomes, and these strains lack morphologically normal peroxisomes. We report the cloning of Pichia pastoris PAS1, the homologue (based on a high level of protein sequence similarity) of the Saccharomyces cerevisiae PAS1. We also describe the creation and characterization of P. pastoris pas1 strains. Electron microscopy on the P. pastoris pas1 cells revealed that they lack morphologically normal peroxisomes, and instead contain membrane-bound structures that appear to be small, mutant peroxisomes, or "peroxisome ghosts." These "ghosts" proliferated in response to induction on peroxisome-requiring carbon sources (oleic acid and methanol), and they were distributed to daughter cells. Biochemical analysis of cell lysates revealed that peroxisomal proteins are induced normally in pas1 cells. Peroxisome ghosts from pas1 cells were purified on sucrose gradients, and biochemical analysis showed that these ghosts, while lacking several peroxisomal proteins, did import varying amounts of several other peroxisomal proteins. The existence of detectable peroxisome ghosts in P. pastoris pas1 cells, and their ability to import some proteins, stands in contrast with the results reported by Erdmann et al. (1991) for the S. cerevisiae pas1 mutant, in which they were unable to detect peroxisome-like structures. We discuss the role of PAS1 in peroxisome biogenesis in light of the new information regarding peroxisome ghosts in pas1 cells.

scholarly journals The Pichia pastoris PER6 gene product is a peroxisomal integral membrane protein essential for peroxisome biogenesis and has sequence similarity to the Zellweger syndrome protein PAF-1.

1996 ◽  
Vol 16 (5) ◽  
pp. 2527-2536 ◽  
Author(s):  
H R Waterham ◽  
Y de Vries ◽  
K A Russel ◽  
W Xie ◽  
M Veenhuis ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Membrane Protein ◽  
Sequence Similarity ◽  
Zellweger Syndrome ◽  
Methylotrophic Yeast ◽  
Integral Membrane Protein ◽  
Biochemical Properties ◽  
Podospora Anserina ◽  
Peroxisome Biogenesis ◽  
Membrane Spanning

We report the cloning of PER6, a gene essential for peroxisome biogenesis in the methylotrophic yeast Pichia pastoris. The PER6 sequence predicts that its product Per6p is a 52-kDa polypeptide with the cysteine-rich C3HC4 motif. Per6p has significant overall sequence similarity with the human peroxisome assembly factor PAF-1, a protein that is defective in certain patients suffering from the peroxisomal disorder Zellweger syndrome, and with car1, a protein required for peroxisome biogenesis and caryogamy in the filamentous fungus Podospora anserina. In addition, the C3HC4 motif and two of the three membrane-spanning segments predicted for Per6p align with the C3HC4 motifs and the two membrane-spanning segments predicted for PAF-1 and car1. Like PAF-1, Per6p is a peroxisomal integral membrane protein. In methanol- or oleic acid-induced cells of per6 mutants, morphologically recognizable peroxisomes are absent. Instead, peroxisomal remnants are observed. In addition, peroxisomal matrix proteins are synthesized but located in the cytosol. The similarities between Per6p and PAF-1 in amino acid sequence and biochemical properties, and between mutants defective in their respective genes, suggest that Per6p is the putative yeast homolog of PAF-1.

Studies on the possible relationships of microbodies and multivesicular bodies to oxalate, endopolygalacturonase, and cellulase (Cx) production by Sclerotinia sclerotiorum

1972 ◽  
Vol 50 (8) ◽  
pp. 1743-1748 ◽  
Author(s):  
Douglas P. Maxwell ◽  
Paul H. Williams ◽  
Martha D. Maxwell
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Enzyme Production ◽  
Functional Role ◽  
Carbon Sources ◽  
Extracellular Enzyme ◽  
Ultrastructural Organization ◽  
Multivesicular Bodies ◽  
Membrane Bound ◽  
High Production

The possible functional role of vesicles and crystal-containing microbodies in the production of oxalate, endopolygalacturonase, or cellulase by Sclerotinia sclerotiorum was investigated. The presence of multivesicular bodies in hyphal tips was not correlated with secretion or production of oxalate or these extracellular hydrolases. More crystal-containing microbodies were present in hyphal tips grown on media which supported greater extracellular enzyme production. No correlation existed between numbers of crystal-containing microbodies in hyphal tips and production of oxalate. Numerous membrane-bound vesicles (0.09–0.18 µm diam) were associated with tips grown on a D-glucose–Na succinate medium which supported high production of oxalate. The general ultrastructural organization of these hyphal tips was similar to that reported for other ascomycetes. Differences in numbers and distributions of organelles were observed between hyphal tips and older hyphae as well as between hyphal tips grown on the different carbon sources.

scholarly journals A Conserved Residue in the Yeast Bem1p SH3 Domain Maintains the High Level of Binding Specificity Required for Function

2011 ◽  
Vol 286 (22) ◽  
pp. 19470-19477 ◽  
Author(s):  
Maryna Gorelik ◽  
Karen Stanger ◽  
Alan R. Davidson
Keyword(s):  
Sequence Similarity ◽  
Consensus Sequence ◽  
Binding Specificity ◽  
Biologically Relevant ◽  
Protein Protein Interaction ◽  
Nonspecific Interactions ◽  
High Level ◽  
Conserved Residue

The yeast Bem1p SH3b and Nbp2p SH3 domains are unusual because they bind to peptides containing the same consensus sequence, yet they perform different functions and display low sequence similarity. In this work, by analyzing the interactions of these domains with six biologically relevant peptides containing the consensus sequence, they are shown to possess finely tuned and distinct binding specificities. We also identify a residue in the Bem1p SH3b domain that inhibits binding, yet is highly conserved for the purpose of preventing nonspecific interactions. Substitution of this residue results in a marked reduction of in vivo function that is caused by titration of the domain away from its proper targets through nonspecific interactions with other proteins. This work provides a clear illustration of the importance of intrinsic binding specificity for the function of protein-protein interaction modules, and the key role of “negative” interactions in determining the specificity of a domain.

Molecular regulation of SREBP function: the Insig-SCAP connection and isoform-specific modulation of lipid synthesis

2004 ◽  
Vol 82 (1) ◽  
pp. 201-211 ◽  
Author(s):  
Ruth McPherson ◽  
Andre Gauthier
Keyword(s):  
Acid Metabolism ◽  
Regulatory Element ◽  
Lipid Synthesis ◽  
Molecular Regulation ◽  
New Information ◽  
Ubiquitin Proteasome ◽  
Sterol Regulatory Element ◽  
Membrane Bound ◽  
Proteasome Pathway

Sterol regulatory element binding proteins (SREBPs) are a family of membrane-bound transcription factors that play a unique and fundamental role in both cholesterol and fatty acid metabolism, relevant to human disease. There are three SREBPs that regulate the expression of over 30 genes. SREBPs are subject to regulation at three levels: proteolytic cleavage, rapid degradation by the ubiquitin-proteasome pathway, and sumoylation. Recently, there have been exciting advances in our understanding of the molecular mechanism of SREBP trafficking and processing with new information on the role of insulin-induced genes and the differential role and regulation of SREBP-1c and -2, which may ultimately lead to novel strategies for the treatment of dyslipidemia and insulin resistance.Key words: SREBP, Insig, SCAP, cholesterol synthesis, lipid metabolism.

scholarly journals Pex19p Interacts with Pex3p and Pex10p and Is Essential for Peroxisome Biogenesis in Pichia pastoris

1999 ◽  
Vol 10 (6) ◽  
pp. 1745-1761 ◽  
Author(s):  
William B. Snyder ◽  
Klaas Nico Faber ◽  
Thibaut J. Wenzel ◽  
Antonius Koller ◽  
Georg H. Lüers ◽  
...  
Keyword(s):  
Amino Acids ◽  
Pichia Pastoris ◽  
Early Stage ◽  
Sequence Similarity ◽  
Chinese Hamster ◽  
Peroxisome Biogenesis ◽  
Amino Terminal ◽  
Acid Protein ◽  
Peroxisomal Targeting ◽  
Two Hybrid

We report the cloning and characterization of Pichia pastoris PEX19 by complementation of a peroxisome-deficient mutant strain. Import of peroxisomal targeting signal 1- and 2-containing peroxisomal matrix proteins is defective inpex19 mutants. PEX19 encodes a hydrophilic 299-amino acid protein with sequence similarity toSaccharomyces cerevisiae Pex19p and human and Chinese hamster PxF, all farnesylated proteins, as well as hypothetical proteins from Caenorhabditis elegans andSchizosaccharomyces pombe. The farnesylation consensus is conserved in PpPex19p but dispensable for function and appears unmodified under the conditions tested. Pex19p localizes predominantly to the cytosolic fraction. Biochemical and two-hybrid analyses confirmed that Pex19p interacts with Pex3p, as seen in S. cerevisiae, but unexpectedly also with Pex10p. Two-hybrid analysis demonstrated that the amino-terminal 42 amino acids of Pex19p interact with the carboxyl-terminal 335 amino acids of Pex3p. In addition, the extreme carboxyl terminus of Pex19p (67 amino acids) is required for interaction with the amino-terminal 380 amino acids of Pex10p. Biochemical and immunofluorescence microscopy analyses ofpex19Δ cells identified the membrane protein Pex3p in peroxisome remnants that were not previously observed in S. cerevisiae. These small vesicular and tubular (early) remnants are morphologically distinct from other Pppex mutant (late) remnants, suggesting that Pex19p functions at an early stage of peroxisome biogenesis.

scholarly journals Peroxisome biogenesis and positioning

2010 ◽  
Vol 38 (3) ◽  
pp. 807-816 ◽  
Author(s):  
Alison Baker ◽  
Imogen A. Sparkes ◽  
Laura-Anne Brown ◽  
Catherine O'Leary-Steele ◽  
Stuart L. Warriner
Keyword(s):  
Endoplasmic Reticulum ◽  
Degradation Pathway ◽  
Matrix Proteins ◽  
Peroxisome Biogenesis ◽  
Environmental Signals ◽  
Targeting Signal ◽  
Membrane Bound ◽  
Plant Life Cycle ◽  
Peroxisome Membrane

Plant peroxisomes are extremely dynamic, moving and undergoing changes of shape in response to metabolic and environmental signals. Matrix proteins are imported via one of two import pathways, depending on the targeting signal within the protein. Each pathway has a specific receptor but utilizes common membrane-bound translocation machinery. Current models invoke receptor recycling, which may involve cycles of ubiquitination. Some components of the import machinery may also play a role in proteolytic turnover of matrix proteins, prompting parallels with the endoplasmic-reticulum-associated degradation pathway. Peroxisome membrane proteins, some of which are imported post-translationally, others of which may traffic to peroxisomes via the endoplasmic reticulum, use distinct proteinaceous machinery. The isolation of mutants defective in peroxisome biogenesis has served to emphasize the important role of peroxisomes at all stages of the plant life cycle.

scholarly journals Phenotypic and Biochemical Comparison of the Carbapenem-Hydrolyzing Activities of Five Plasmid-Borne AmpC β-Lactamases

2010 ◽  
Vol 54 (11) ◽  
pp. 4556-4560 ◽  
Author(s):  
Hedi Mammeri ◽  
Hélène Guillon ◽  
François Eb ◽  
Patrice Nordmann
Keyword(s):  
Biochemical Analysis ◽  
Carbapenem Resistance ◽  
Catalytic Efficiency ◽  
Wild Type ◽  
E Coli ◽  
Genes Encoding ◽  
High Level ◽  
Biochemical Comparison ◽  
Outer Membrane Permeability

ABSTRACT The CMY-2, ACT-1, DHA-1, ACC-1, and FOX-1 enzymes are representative of five plasmid-mediated AmpC (pAmpC) β-lactamase clusters. Resistance to imipenem has been reported in Enterobacteriaceae as a result of pAmpC expression combined with decreased outer membrane permeability. The aim of this study was to determine the role of different pAmpCs in carbapenem resistance and to define the structure/activity relationship supporting carbapenemase activity. The ampC genes encoding the five pAmpCs and the chromosomal AmpC of Escherichia coli EC6, which was used as a reference cephalosporinase, were cloned and introduced into wild-type E. coli TOP10 and OmpC/OmpF porin-deficient E. coli HB4 strains. The MICs of β-lactams for the recombinant strains revealed that CMY-2, ACT-1, and DHA-1 β-lactamases conferred a high level of resistance to ceftazidime and cefotaxime once expressed in E. coli TOP10 and reduced significantly the susceptibility to imipenem once expressed in E. coli HB4. In contrast, FOX-1 and ACC-1 enzymes did not confer resistance to imipenem. Biochemical analysis showed that CMY-2 β-lactamase and, to a lesser extent, ACT-1 exhibited the highest catalytic efficiency toward imipenem and showed low Km values. A modeling study revealed that the large R2 binding site of these two enzymes may support the carbapenemase activity. Therefore, CMY-2-type, ACT-1-type, and DHA-1-type β-lactamases may promote the emergence of carbapenem resistance in porin-deficient clinical isolates.

scholarly journals The Role of Ribosomal Protein S6 Kinases in Plant Homeostasis

2021 ◽  
Vol 8 ◽  
Author(s):  
Irabonosi Obomighie ◽  
Kestutis Lapenas ◽  
Billy E. Murphy ◽  
Alexander M. C. Bowles ◽  
Ulrike Bechtold ◽  
...  
Keyword(s):  
Sequence Similarity ◽  
Tor Pathway ◽  
The Past ◽  
Ribosomal Protein S6 ◽  
Downstream Effectors ◽  
Regulation Mechanisms ◽  
Ribosomal S6 Kinase ◽  
High Level

The p70 ribosomal S6 kinase (S6K) family is a group of highly conserved kinases in eukaryotes that regulates cell growth, cell proliferation, and stress response via modulating protein synthesis and ribosomal biogenesis. S6Ks are downstream effectors of the Target of Rapamycin (TOR) pathway, which connects nutrient and energy signaling to growth and homeostasis, under normal and stress conditions. The plant S6K family includes two isoforms, S6K1 and S6K2, which, despite their high level of sequence similarity, have distinct functions and regulation mechanisms. Significant advances on the characterization of human S6Ks have occurred in the past few years, while studies on plant S6Ks are scarce. In this article, we review expression and activation of the two S6K isoforms in plants and we discuss their roles in mediating responses to stresses and developmental cues.

scholarly journals Phosphorylation-dependent Pex11p and Fis1p interaction regulates peroxisome division

2012 ◽  
Vol 23 (7) ◽  
pp. 1307-1315 ◽  
Author(s):  
Saurabh Joshi ◽  
Gaurav Agrawal ◽  
Suresh Subramani
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Endoplasmic Reticulum ◽  
Pichia Pastoris ◽  
Peroxisome Biogenesis ◽  
Peroxisomal Membrane ◽  
Protein Levels ◽  
Protein Biogenesis ◽  
Peroxisome Division ◽  
Dependent Interaction

Peroxisome division is regulated by the conserved peroxin Pex11p. In Saccharomyces cerevisiae (Sc), induction of the phosphoprotein ScPex11p coincides with peroxisome biogenesis. We show that the ScPex11p homologue in Pichia pastoris (PpPex11p) is phosphorylated at serine 173. PpPex11p expression and phosphorylation are induced in oleate and coordinated with peroxisome biogenesis. PpPex11p transits to peroxisomes via the endoplasmic reticulum (ER). PpPex11p is unstable and ER restricted gin pex3Δ and pex19Δ cells, which are impaired in peroxisomal membrane protein biogenesis. In oleate medium, the P. pastoris mutants pex11A (constitutively unphosphorylated; S173A) and pex11D (constitutively phosphorylated; S173D) exhibit juxtaposed elongated peroxisomes (JEPs) and hyperdivided forms, respectively, although protein levels remain unchanged. In contrast with ScPex11p, the ER-to-peroxisome translocation in P. pastoris is phosphorylation independent, and the phosphorylation occurs at the peroxisome. We show that PpPex11p interacts with the peroxisome fission machinery via PpFis1p and is regulated by phosphorylation because PpPex11p and PpPex11Dp interact more strongly with PpFis1p than PpPex11Ap. Neither PpPex11p nor PpFis1p is necessary for peroxisome division in methanol medium. We propose a model for the role of PpPex11p in the regulation of peroxisome division through a phosphorylation-dependent interaction with the fission machinery, providing novel insights into peroxisome morphogenesis.

scholarly journals Information technologies in accounting. prospects and problems

2021 ◽  
pp. 17-20
Author(s):  
Vadym RATYNSKYI
Keyword(s):  
Information Technology ◽  
Information Technologies ◽  
International Standards ◽  
Automated System ◽  
Software Products ◽  
Advantages And Disadvantages ◽  
New Information ◽  
Modern Level ◽  
High Level

The issues of application of new information technologies in accounting are considered. Peculiarities of automated accounting in the conditions of domestic reality are singled out, methodical principles of informatization of administrative activity are shown. The classification of software products used for automation of accounting is made, the rating of the most widespread programs for informatization of administrative activity in our country is resulted. The main advantages and disadvantages of using information technology in the organization of accounting are shown. Problems of automation of administrative activity at transition to the international standards are considered. A critical assessment of well-known authors and scientists of the modern level of automated accounting in economics is given. Particular attention is paid to the use of remote hardware and software resources in solving problems of informatization of management. Prospects of application in the account of the expert systems constructed on the basis of high-level software products are considered. Some problems of information protection that pose a threat to the use of information technology in management tasks are highlighted. The role of the person in the automated system of accounting, irreplaceability of experience and professionalism of the accountant at any level of development of information technologies is shown. All this makes it possible to create a single information space for the enterprise. Studies have shown that only the integrated development of conceptual accounting models, transformed into mathematical and algorithmic models, in combination with information technology will make it possible to raise accounting to a higher level. Thus, the development of information technologies and the digitalization of the economy make it possible to change the functions performed by accounting services and transform accountants from information input operators into economists-controllers and information users.

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