scholarly journals Recognition and Chaperoning by Pex19, Followed by Trafficking and Membrane Insertion of the Peroxisome Proliferation Protein, Pex11

Cells ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 157
Author(s):  
Katarzyna M. Zientara-Rytter ◽  
Shanmuga S. Mahalingam ◽  
Jean-Claude Farré ◽  
Krypton Carolino ◽  
Suresh Subramani

Pex11, an abundant peroxisomal membrane protein (PMP), is required for division of peroxisomes and is robustly imported to peroxisomal membranes. We present a comprehensive analysis of how the Pichia pastoris Pex11 is recognized and chaperoned by Pex19, targeted to peroxisome membranes and inserted therein. We demonstrate that Pex11 contains one Pex19-binding site (Pex19-BS) that is required for Pex11 insertion into peroxisomal membranes by Pex19, but is non-essential for peroxisomal trafficking. We provide extensive mutational analyses regarding the recognition of Pex19-BS in Pex11 by Pex19. Pex11 also has a second, Pex19-independent membrane peroxisome-targeting signal (mPTS) that is preserved among Pex11-family proteins and anchors the human HsPex11γ to the outer leaflet of the peroxisomal membrane. Thus, unlike most PMPs, Pex11 can use two mechanisms of transport to peroxisomes, where only one of them depends on its direct interaction with Pex19, but the other does not. However, Pex19 is necessary for membrane insertion of Pex11. We show that Pex11 can self-interact, using both homo- and/or heterotypic interactions involving its N-terminal helical domains. We demonstrate that Pex19 acts as a chaperone by interacting with the Pex19-BS in Pex11, thereby protecting Pex11 from spontaneous oligomerization that would otherwise cause its aggregation and subsequent degradation.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hitomi Nakamura ◽  
Moeka Yoshikawa ◽  
Naoko Oda-Ueda ◽  
Tadashi Ueda ◽  
Takatoshi Ohkuri

AbstractGenerally, intermolecular disulfide bond contribute to the conformational protein stability. To identify sites where intermolecular disulfide bond can be introduced into the Fab’s constant domain of the therapeutic IgG, Fab mutants were predicted using the MOE software, a molecular simulator, and expressed in Pichia pastoris. SDS-PAGE analysis of the prepared Fab mutants from P. pastoris indicated that among the nine analyzed Fab mutants, the F130C(H):Q124C(L), F174C(H):S176C(L), V177C(H):Q160C(L), F174C(H):S162C(L), F130C(H):S121C(L), and A145C(H):F116C(L) mutants mostly formed intermolecular disulfide bond. All these mutants showed increased thermal stability compared to that of Fab without intermolecular disulfide bond. In the other mutants, the intermolecular disulfide bond could not be completely formed, and the L132C(H):F118C(L) mutant showed only a slight decrease in binding activity and β-helix content, owing to the exertion of adverse intermolecular disulfide bond effects. Thus, our comprehensive analysis reveals that the introduction of intermolecular disulfide bond in the Fab’s constant domain is possible at various locations. These findings provide important insights for accomplishing human Fab stabilization.


2011 ◽  
Vol 25 (3) ◽  
pp. 511-536 ◽  
Author(s):  
Peter M. Johnson ◽  
Thomas J. Lopez ◽  
Juan Manuel Sanchez

SYNOPSIS We provide a comprehensive analysis of special items and the characteristics of the firms that recognize them. Our analysis reveals that the temporal frequency, magnitude, and persistence of special items has increased significantly in the last 30 years, and that such increases are primarily driven by negative special items. More recently, however, our evidence is consistent with both a decline in frequency and magnitude of negative special items. On the other hand, we find that the frequency of reporting of positive special items, which remained relatively constant through 2002, has increased in more recent years. We also find strong evidence that subsequent special item reporting is an increasing function of the frequency of “prior” special item reporting. Using a random subsample of firms reporting special items, we document that 22 percent of the amounts reported in Compustat do not reconcile with the amounts reported on the firms' actual financial statements. Our comprehensive analysis should be of interest to regulators, academics, and managers interested in the implications of special items on firm-related consequences such as future earnings and firm value. Our examination can also serve as a catalyst for researchers interested in extending this important area of inquiry.


2017 ◽  
Vol 27 (03) ◽  
pp. 1850037 ◽  
Author(s):  
Yasir ◽  
Ning Wu ◽  
Xiaoqiang Zhang

This paper proposes compact hardware implementations of 64-bit NESSIE proposed MISTY1 block cipher for area constrained and low power ASIC applications. The architectures comprise only one round MISTY1 block cipher algorithm having optimized FO/FI function by re-utilizing S9/S7 substitution functions. A focus is also made on efficient logic implementations of S9 and S7 substitution functions using common sub-expression elimination (CSE) and parallel AND/XOR gates hierarchy. The proposed architecture 1 generates extended key with independent FI function and is suitable for MISTY1 8-rounds implementation. On the other hand, the proposed architecture 2 uses a single FO/FI function for both MISTY1 round function as well as extended key generation and can be employed for MISTY1 [Formula: see text] rounds. To analyze the performance and covered area for ASICs, Synopsys Design Complier, SMIC 0.18[Formula: see text][Formula: see text]m @ 1.8[Formula: see text]V is used. The hardware constituted 3041 and 2331 NAND gates achieving throughput of 171 and 166 Mbps for 8 rounds implementation of architectures 1 and 2, respectively. Comprehensive analysis of proposed designs is covered in this paper.


1997 ◽  
Vol 137 (6) ◽  
pp. 1265-1278 ◽  
Author(s):  
Gary A. Eitzen ◽  
Rachel K. Szilard ◽  
Richard A. Rachubinski

Pex mutants of the yeast Yarrowia lipolytica are defective in peroxisome assembly. The mutant strain pex16-1 lacks morphologically recognizable peroxisomes. Most peroxisomal proteins are mislocalized to a subcellular fraction enriched for cytosol in pex16 strains, but a subset of peroxisomal proteins is localized at, or near, wild-type levels to a fraction typically enriched for peroxisomes. The PEX16 gene was isolated by functional complementation of the pex16-1 strain and encodes a protein, Pex16p, of 391 amino acids (44,479 D). Pex16p has no known homologues. Pex16p is a peripheral protein located at the matrix face of the peroxisomal membrane. Substitution of the carboxylterminal tripeptide Ser-Thr-Leu, which is similar to the consensus sequence of peroxisomal targeting signal 1, does not affect targeting of Pex16p to peroxisomes. Pex16p is synthesized in wild-type cells grown in glucose-containing media, and its levels are modestly increased by growth of cells in oleic acid–containing medium. Overexpression of the PEX16 gene in oleic acid– grown Y. lipolytica leads to the appearance of a small number of enlarged peroxisomes, which contain the normal complement of peroxisomal proteins at levels approaching those of wild-type peroxisomes.


2005 ◽  
Vol 79 (4) ◽  
pp. 2366-2374 ◽  
Author(s):  
Pilar Perez-Romero ◽  
Ryan E. Tyler ◽  
Johanna R. Abend ◽  
Monica Dus ◽  
Michael J. Imperiale

ABSTRACT We previously showed that the adenovirus IVa2 and L1 52/55-kDa proteins interact in infected cells and the IVa2 protein is part of two virus-specific complexes (x and y) formed in vitro with repeated elements of the packaging sequence called the A1-A2 repeats. Here we demonstrate that both the IVa2 and L1 52/55-kDa proteins bind in vivo to the packaging sequence and that each protein-DNA interaction is independent of the other. There is a strong and direct interaction of the IVa2 protein with DNA in vitro. This interaction is observed when probes containing the A1-A2 or A4-A5 repeats are used, but it is not found by using an A5-A6 probe. Furthermore, we show that complex x is likely a heterodimer of IVa2 and an unknown viral protein, while complex y is a monomer or multimer of IVa2. No in vitro interaction of purified L1 52/55-kDa protein with the packaging sequence was found, suggesting that the L1 52/55-kDa protein-DNA interaction may be mediated by an intermediate protein. Results support roles for both the L1 52/55-kDa and IVa2 proteins in DNA encapsidation.


1999 ◽  
Vol 112 (10) ◽  
pp. 1579-1590 ◽  
Author(s):  
C.C. Chang ◽  
S. South ◽  
D. Warren ◽  
J. Jones ◽  
A.B. Moser ◽  
...  

Zellweger syndrome and related disorders represent a group of lethal, genetically heterogeneous diseases. These peroxisome biogenesis disorders (PBDs) are characterized by defective peroxisomal matrix protein import and comprise at least 10 complementation groups. The genes defective in seven of these groups and more than 90% of PBD patients are now known. Here we examine the distribution of peroxisomal membrane proteins in fibroblasts from PBD patients representing the seven complementation groups for which the mutant gene is known. Peroxisomes were detected in all PBD cells, indicating that the ability to form a minimal peroxisomal structure is not blocked in these mutants. We also observed that peroxisome abundance was reduced fivefold in PBD cells that are defective in the PEX1, PEX5, PEX12, PEX6, PEX10, and PEX2 genes. These cell lines all display a defect in the import of proteins with the type-1 peroxisomal targeting signal (PTS1). In contrast, peroxisome abundance was unaffected in cells that are mutated in PEX7 and are defective only in the import of proteins with the type-2 peroxisomal targeting signal. Interestingly, a fivefold reduction in peroxisome abundance was also observed for cells lacking either of two PTS1-targeted peroxisomal beta-oxidation enzymes, acyl-CoA oxidase and 2-enoyl-CoA hydratase/D-3-hydroxyacyl-CoA dehydrogenase. These results indicate that reduced peroxisome abundance in PBD cells may be caused by their inability to import these PTS1-containing enzymes. Furthermore, the fact that peroxisome abundance is influenced by peroxisomal 105-oxidation activities suggests that there may be metabolic control of peroxisome abundance.


2013 ◽  
Vol 5 (2) ◽  
pp. 1-20 ◽  
Author(s):  
Matthias Baldauf ◽  
Peter Fröhlich ◽  
Jasmin Buchta ◽  
Theresa Stürmer

Today’s smartphones provide the technical means to serve as interfaces for public displays in various ways. Even though recent research has identified several new approaches for mobile-display interaction, inter-technique comparisons of respective methods are scarce. The authors conducted an experimental user study on four currently relevant mobile-display interaction techniques (‘Touchpad’, ‘Pointer’, ‘Mini Video’, and ‘Smart Lens’) and learned that their suitability strongly depends on the task and use case at hand. The study results indicate that mobile-display interactions based on a traditional touchpad metaphor are time-consuming but highly accurate in standard target acquisition tasks. The direct interaction techniques Mini Video and Smart Lens had comparably good completion times, and especially Mini Video appeared to be best suited for complex visual manipulation tasks like drawing. Smartphone-based pointing turned out to be generally inferior to the other alternatives. Examples for the application of these differentiated results to real-world use cases are provided.


Author(s):  
Andrzej Wiśniewski ◽  
Marcin Chłoń ◽  
Marcel Weiss ◽  
Katarzyna Pyżewicz ◽  
Witold Migal

Abstract This paper attempts to show that manufacture of Micoquian bifacial backed tools was structured. Data for this study were collected using a comprehensive analysis of artefacts from the site Pietraszyn 49a, Poland, which is dated to the beginning of Marine Isotope Stage 3. Based on the whole data set, it was possible to distinguish four stages of the manufacturing process. During manufacturing, both mineral hammer and organic hammer were used. The tools were usually shaped due to distinct hierarchization of faces. The study has also shown that the shape of bifacial tools from Pietraszyn 49a is very similar to the other Micoquian examples from central Europe. The ways of shaping of some tools are finding their counterparts also in the Early Upper Palaeolithic inventories, but the similarities are rather limited to the narrow range of preparation of bifacial form.


2004 ◽  
Vol 78 (9) ◽  
pp. 4744-4752 ◽  
Author(s):  
Beatriz Navarro ◽  
Luisa Rubino ◽  
Marcello Russo

ABSTRACT Open reading frame 1 in the viral genome of Cymbidium ringspot virus encodes a 33-kDa protein (p33), which was previously shown to localize to the peroxisomal membrane in infected and transgenic plant cells. To determine the sequence requirements for the organelle targeting and membrane insertion, the protein was expressed in the yeast Saccharomyces cerevisiae in native form (33K) or fused to the green fluorescent protein (33KGFP). Cell organelles were identified by immunolabeling of marker proteins. In addition, peroxisomes were identified by simultaneous expression of the red fluorescent protein DsRed containing a peroxisomal targeting signal and mitochondria by using the dye MitoTracker. Fluorescence microscopy showed the 33KGFP fusion protein concentrated in a few large bodies colocalizing with peroxisomes. These bodies were shown by electron microscopy to be composed by aggregates of peroxisomes, a few mitochondria and endoplasmic reticulum (ER) strands. In immunoelectron microscopy, antibodies to p33 labeled the peroxisomal clumps. Biochemical analysis suggested that p33 is anchored to the peroxisomal membrane through a segment of ca. 7 kDa, which corresponds to the sequence comprising two hydrophobic transmembrane domains and a hydrophilic interconnecting loop. Analysis of deletion mutants confirmed these domains as essential components of the p33 peroxisomal targeting signal, together with a cluster of three basic amino acids (KRR). In yeast mutants lacking peroxisomes p33 was detected in the ER. The possible involvement of the ER as an intermediate step for the integration of p33 into the peroxisomal membrane is discussed.


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