scholarly journals Autophagy Inhibitors Do Not Restore Peroxisomal Functions in Cells With the Most Common Peroxisome Biogenesis Defect

2021 ◽  
Vol 9 ◽  
Author(s):  
Femke C. C. Klouwer ◽  
Kim D. Falkenberg ◽  
Rob Ofman ◽  
Janet Koster ◽  
Démi van Gent ◽  
...  
Keyword(s):  
Matrix Protein ◽  
Protein Import ◽  
Therapeutic Option ◽  
Cell Types ◽  
Matrix Proteins ◽  
Peroxisome Biogenesis ◽  
Metabolic Functions ◽  
Minimal Improvement ◽  
Different Cell Types ◽  
Autophagy Inhibition

Peroxisome biogenesis disorders within the Zellweger spectrum (PBD-ZSDs) are most frequently associated with the c.2528G>A (p.G843D) mutation in the PEX1 gene (PEX1-G843D), which results in impaired import of peroxisomal matrix proteins and, consequently, defective peroxisomal functions. A recent study suggested that treatment with autophagy inhibitors, in particular hydroxychloroquine, would be a potential therapeutic option for PBD-ZSD patients carrying the PEX1-G843D mutation. Here, we studied whether autophagy inhibition by chloroquine, hydroxychloroquine and 3-methyladenine indeed can improve peroxisomal functions in four different cell types with the PEX1-G843D mutation, including primary patient cells. Furthermore, we studied whether autophagy inhibition may be the mechanism underlying the previously reported improvement of peroxisomal functions by L-arginine in PEX1-G843D cells. In contrast to L-arginine, we observed no improvement but a worsening of peroxisomal metabolic functions and peroxisomal matrix protein import by the autophagy inhibitors, while genetic knock-down of ATG5 and NBR1 in primary patient cells resulted in only a minimal improvement. Our results do not support the use of autophagy inhibitors as potential treatment for PBD-ZSD patients, whereas L-arginine remains a therapeutically promising compound.

scholarly journals Peroxisomes exhibit compromised structure and matrix protein content in SARS-CoV-2-infected cells

2021 ◽  
pp. mbc.E21-02-0074
Author(s):  
Barbara Knoblach ◽  
Ray Ishida ◽  
Tom C. Hobman ◽  
Richard A. Rachubinski
Keyword(s):  
Protein Content ◽  
Matrix Protein ◽  
Protein Import ◽  
Structural Integrity ◽  
Matrix Proteins ◽  
Peroxisome Biogenesis ◽  
Peroxisomal Membrane ◽  
Antiviral Signaling ◽  
Infected Cells ◽  
Novel Coronavirus

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus that has triggered global health and economic crises. Here we report the effects of SARS-CoV-2 infection on peroxisomes of human cell lines, Huh-7 and SK-N-SH. Peroxisomes undergo dramatic changes in morphology in SARS-CoV-2-infected cells. Rearrangement of peroxisomal membranes is followed by redistribution of peroxisomal matrix proteins to the cytosol, resulting in a dramatic decrease in the numbers of mature peroxisomes. The SARS-CoV-2 ORF14 protein was shown to interact physically with human PEX14, a peroxisomal membrane protein required for matrix protein import and peroxisome biogenesis. Given the important roles of peroxisomes in innate immunity, SARS-CoV-2 may directly target peroxisomes, resulting in loss of peroxisome structural integrity, matrix protein content and ability to function in antiviral signaling. [Media: see text]

scholarly journals The Peroxisome Biogenesis Factors Pex4p, Pex22p, Pex1p, and Pex6p Act in the Terminal Steps of Peroxisomal Matrix Protein Import

2000 ◽  
Vol 20 (20) ◽  
pp. 7516-7526 ◽  
Author(s):  
Cynthia S. Collins ◽  
Jennifer E. Kalish ◽  
James C. Morrell ◽  
J. Michael McCaffery ◽  
Stephen J. Gould
Keyword(s):  
Matrix Protein ◽  
Protein Import ◽  
Protein Translocation ◽  
Matrix Proteins ◽  
Peroxisome Biogenesis ◽  
Peroxisomal Membrane ◽  
The Matrix ◽  
Peroxisomal Targeting ◽  
Targeting Signal ◽  
Mutant Cells

ABSTRACT Peroxisomes are independent organelles found in virtually all eukaryotic cells. Genetic studies have identified more than 20PEX genes that are required for peroxisome biogenesis. The role of most PEX gene products, peroxins, remains to be determined, but a variety of studies have established that Pex5p binds the type 1 peroxisomal targeting signal and is the import receptor for most newly synthesized peroxisomal matrix proteins. The steady-state abundance of Pex5p is unaffected in mostpex mutants of the yeast Pichia pastorisbut is severely reduced in pex4 andpex22 mutants and moderately reduced in pex1and pex6 mutants. We used these subphenotypes to determine the epistatic relationships among several groups ofpex mutants. Our results demonstrate that Pex4p acts after the peroxisome membrane synthesis factor Pex3p, the Pex5p docking factors Pex13p and Pex14p, the matrix protein import factors Pex8p, Pex10p, and Pex12p, and two other peroxins, Pex2p and Pex17p. Pex22p and the interacting AAA ATPases Pex1p and Pex6p were also found to act after Pex10p. Furthermore, Pex1p and Pex6p were found to act upstream of Pex4p and Pex22p. These results suggest that Pex1p, Pex4p, Pex6p, and Pex22p act late in peroxisomal matrix protein import, after matrix protein translocation. This hypothesis is supported by the phenotypes of the corresponding mutant strains. As has been shown previously for P. pastoris pex1,pex6, and pex22 mutant cells, we show here thatpex4Δ mutant cells contain peroxisomal membrane protein-containing peroxisomes that import residual amounts of peroxisomal matrix proteins.

scholarly journals The unique degradation pathway of the PTS2 receptor, Pex7, is dependent on the PTS receptor/coreceptor, Pex5 and Pex20

2014 ◽  
Vol 25 (17) ◽  
pp. 2634-2643 ◽  
Author(s):  
Danielle Hagstrom ◽  
Changle Ma ◽  
Soumi Guha-Polley ◽  
Suresh Subramani
Keyword(s):  
Matrix Protein ◽  
Protein Import ◽  
Degradation Pathway ◽  
Matrix Proteins ◽  
Receptor Recycling ◽  
Wild Type ◽  
The Matrix ◽  
Peroxisomal Targeting ◽  
Targeting Signals ◽  
The Stability

Peroxisomal matrix protein import uses two peroxisomal targeting signals (PTSs). Most matrix proteins use the PTS1 pathway and its cargo receptor, Pex5. The PTS2 pathway is dependent on another receptor, Pex7, and its coreceptor, Pex20. We found that during the matrix protein import cycle, the stability and dynamics of Pex7 differ from those of Pex5 and Pex20. In Pichia pastoris, unlike Pex5 and Pex20, Pex7 is constitutively degraded in wild-type cells but is stabilized in pex mutants affecting matrix protein import. Degradation of Pex7 is more prevalent in cells grown in methanol, in which the PTS2 pathway is nonessential, in comparison with oleate, suggesting regulation of Pex7 turnover. Pex7 must shuttle into and out of peroxisomes before it is polyubiquitinated and degraded by the proteasome. The shuttling of Pex7, and consequently its degradation, is dependent on the receptor recycling pathways of Pex5 and Pex20 and relies on an interaction between Pex7 and Pex20. We also found that blocking the export of Pex20 from peroxisomes inhibits PTS1-mediated import, suggesting sharing of limited components in the export of PTS receptors/coreceptors. The shuttling and stability of Pex7 are divergent from those of Pex5 and Pex20, exemplifying a novel interdependence of the PTS1 and PTS2 pathways.

scholarly journals Cell-Based Therapies for Heart Failure

2021 ◽  
Vol 12 ◽  
Author(s):  
Antonio Carlos Campos de Carvalho ◽  
Tais H. Kasai-Brunswick ◽  
Adriana Bastos Carvalho
Keyword(s):  
Heart Failure ◽  
Heart Diseases ◽  
Therapeutic Option ◽  
Cell Types ◽  
World Population ◽  
Future Perspectives ◽  
Cell Therapies ◽  
Ischemic Heart Diseases ◽  
Efficacious Treatment ◽  
Different Cell Types

Heart failure has reached epidemic proportions with the advances in cardiovascular therapies for ischemic heart diseases and the progressive aging of the world population. Efficient pharmacological therapies are available for treating heart failure, but unfortunately, even with optimized therapy, prognosis is often poor. Their last therapeutic option is, therefore, a heart transplantation with limited organ supply and complications related to immunosuppression. In this setting, cell therapies have emerged as an alternative. Many clinical trials have now been performed using different cell types and injection routes. In this perspective, we will analyze the results of such trials and discuss future perspectives for cell therapies as an efficacious treatment of heart failure.

scholarly journals Modulation of In Vivo Migratory Function of α2β1 Integrin in Mouse Liver

1997 ◽  
Vol 8 (10) ◽  
pp. 1863-1875 ◽  
Author(s):  
Wai-chi Ho ◽  
Christine Heinemann ◽  
Dolores Hangan ◽  
Shashi Uniyal ◽  
Vincent L. Morris ◽  
...  
Keyword(s):  
Mouse Liver ◽  
Cell Movement ◽  
Liver Parenchyma ◽  
Cell Types ◽  
Optimal Level ◽  
Matrix Proteins ◽  
Different Cell Types ◽  
Α2β1 Integrin

We report herein that expression of α2β1 integrin increased human erythroleukemia K562 transfectant (KX2C2) cell movement after extravasation into liver parenchyma. In contrast, a previous study demonstrated that α2β1 expression conferred a stationary phenotype to human rhabdomyosarcoma RD transfectant (RDX2C2) cells after extravasation into the liver. We therefore assessed the adhesive and migratory function of α2β1 on KX2C2 and RDX2C2 cells using a α2β1-specific stimulatory monoclonal antibody (mAb), JBS2, and a blocking mAb, BHA2.1. In comparison with RDX2C2 cells, KX2C2 were only weakly adherent to collagen and laminin. JBS2 stimulated α2β1-mediated interaction of KX2C2 cells with both collagen and laminin resulting in increases in cell movement on both matrix proteins. In the presence of Mn2+, JBS2-stimulated adhesion on collagen beyond an optimal level for cell movement. In comparison, an increase in RDX2C2 cell movement on collagen required a reduction in its adhesive strength provided by the blocking mAb BHA2.1. Consistent with these in vitro findings, in vivo videomicroscopy revealed that α2β1-mediated postextravasation cell movement of KX2C2 cells in the liver tissue could also be stimulated by JBS2. Thus, results demonstrate that α2β1 expression can modulate postextravasation cell movement by conferring either a stationary or motile phenotype to different cell types. These findings may be related to the differing metastatic activities of different tumor cell types.

scholarly journals Reevaluation of the role of Pex1 and dynamin-related proteins in peroxisome membrane biogenesis

2015 ◽  
Vol 211 (5) ◽  
pp. 1041-1056 ◽  
Author(s):  
Alison M. Motley ◽  
Paul C. Galvin ◽  
Lakhan Ekal ◽  
James M. Nuttall ◽  
Ewald H. Hettema
Keyword(s):  
Protein Delivery ◽  
Matrix Protein ◽  
Protein Import ◽  
De Novo ◽  
Primary Role ◽  
Peroxisome Biogenesis ◽  
Peroxisomal Membrane ◽  
Related Proteins ◽  
Peroxisome Membrane

A recent model for peroxisome biogenesis postulates that peroxisomes form de novo continuously in wild-type cells by heterotypic fusion of endoplasmic reticulum–derived vesicles containing distinct sets of peroxisomal membrane proteins. This model proposes a role in vesicle fusion for the Pex1/Pex6 complex, which has an established role in matrix protein import. The growth and division model proposes that peroxisomes derive from existing peroxisomes. We tested these models by reexamining the role of Pex1/Pex6 and dynamin-related proteins in peroxisome biogenesis. We found that induced depletion of Pex1 blocks the import of matrix proteins but does not affect membrane protein delivery to peroxisomes; markers for the previously reported distinct vesicles colocalize in pex1 and pex6 cells; peroxisomes undergo continued growth if fission is blocked. Our data are compatible with the established primary role of the Pex1/Pex6 complex in matrix protein import and show that peroxisomes in Saccharomyces cerevisiae multiply mainly by growth and division.

scholarly journals Assembly of alcohol oxidase in peroxisomes of the yeast Hansenula polymorpha requires the cofactor flavin adenine dinucleotide.

1994 ◽  
Vol 5 (8) ◽  
pp. 829-837 ◽  
Author(s):  
M E Evers ◽  
V I Titorenko ◽  
I J van der Klei ◽  
W Harder ◽  
M Veenhuis
Keyword(s):  
Molecular Chaperone ◽  
Matrix Protein ◽  
Protein Import ◽  
Flavin Adenine Dinucleotide ◽  
Hansenula Polymorpha ◽  
Alcohol Oxidase ◽  
Auxotrophic Mutant ◽  
Matrix Proteins ◽  
Wild Type ◽  
Wild Type Control

The peroxisomal flavoprotein alcohol oxidase (AO) is an octamer (600 kDa) consisting of eight identical subunits, each of which contains one flavin adenine dinucleotide molecule as a cofactor. Studies on a riboflavin (Rf) auxotrophic mutant of the yeast Hansenula polymorpha revealed that limitation of the cofactor led to drastic effects on AO import and assembly as well as peroxisome proliferation. Compared to wild-type control cells Rf-limitation led to 1) reduced levels of AO protein, 2) reduced levels of correctly assembled and activated AO inside peroxisomes, 3) a partial inhibition of peroxisomal protein import, leading to the accumulation of precursors of matrix proteins in the cytosol, and 4) a significant increase in peroxisome number. We argue that the inhibition of import may result from the saturation of a peroxisomal molecular chaperone under conditions that normal assembly of a major matrix protein inside the target organelle is prevented.

scholarly journals Evolution toward beta common chain receptor usage links the matrix proteins of HIV-1 and its ancestors to human erythropoietin

2020 ◽  
Vol 118 (2) ◽  
pp. e2021366118
Author(s):  
Francesca Caccuri ◽  
Pasqualina D’Ursi ◽  
Matteo Uggeri ◽  
Antonella Bugatti ◽  
Pietro Mazzuca ◽  
...  
Keyword(s):  
Matrix Protein ◽  
Molecular Mimicry ◽  
Cell Types ◽  
Biological Data ◽  
Matrix Proteins ◽  
Target Cells ◽  
Human Erythropoietin ◽  
The Matrix ◽  
The Difference ◽  
Hiv 1

The HIV-1 matrix protein p17 (p17) is a pleiotropic molecule impacting on different cell types. Its interaction with many cellular proteins underlines the importance of the viral protein as a major determinant of human specific adaptation. We previously showed the proangiogenic capability of p17. Here, by integrating functional analysis and receptor binding, we identify a functional epitope that displays molecular mimicry with human erythropoietin (EPO) and promotes angiogenesis through common beta chain receptor (βCR) activation. The functional EPO-like epitope was found to be present in the matrix protein of HIV-1 ancestors SIV originated in chimpanzees (SIVcpz) and gorillas (SIVgor) but not in that of HIV-2 and its ancestor SIVsmm from sooty mangabeys. According to biological data, evolution of the EPO-like epitope showed a clear differentiation between HIV-1/SIVcpz-gor and HIV-2/SIVsmm branches, thus highlighting this epitope on p17 as a divergent signature discriminating HIV-1 and HIV-2 ancestors. P17 is known to enhance HIV-1 replication. Similarly to other βCR ligands, p17 is capable of attracting and activating HIV-1 target cells and promoting a proinflammatory microenvironment. Thus, it is tempting to speculate that acquisition of an epitope on the matrix proteins of HIV-1 ancestors capable of triggering βCR may have represented a critical step to enhance viral aggressiveness and early human-to-human SIVcpz/gor dissemination. The hypothesis that the p17/βCR interaction and βCR abnormal stimulation may also play a role in sustaining chronic activation and inflammation, thus marking the difference between HIV-1 and HIV-2 in term of pathogenicity, needs further investigation.

The AAA peroxins Pex1p and Pex6p function as dislocases for the ubiquitinated peroxisomal import receptor Pex5p

2008 ◽  
Vol 36 (1) ◽  
pp. 99-104 ◽  
Author(s):  
Harald W. Platta ◽  
Mykhaylo O. Debelyy ◽  
Fouzi El Magraoui ◽  
Ralf Erdmann
Keyword(s):  
Matrix Protein ◽  
Protein Import ◽  
Matrix Proteins ◽  
Genetic Dissection ◽  
Cellular Functions ◽  
Peroxisomal Membrane ◽  
Aaa Atpase ◽  
Ubiquitin Conjugating Enzyme ◽  
Core Components ◽  
Import Receptor

The discovery of the peroxisomal ATPase Pex1p triggered the beginning of the research on AAA (ATPase associated with various cellular activities) proteins and the genetic dissection of peroxisome biogenesis. Peroxisomes are virtually ubiquitous organelles, which are connected to diverse cellular functions. The highly diverse and adaptive character of peroxisomes is accomplished by modulation of their enzyme content, which is mediated by dynamically operating protein-import machineries. The import of matrix proteins into the peroxisomal lumen has been described as the ATP-consuming step, but the corresponding reaction, as well as the ATPase responsible, had been obscure for nearly 15 years. Recent work using yeast and human fibroblast cells has identified the peroxisomal AAA proteins Pex1p and Pex6p as mechano-enzymes and core components of a complex which dislocates the cycling import receptor Pex5p from the peroxisomal membrane back to the cytosol. This AAA-mediated process is regulated by the ubiquitination status of the receptor. Pex4p [Ubc10p (ubiquitin-conjugating enzyme 10)]-catalysed mono-ubiquitination of Pex5p primes the receptor for recycling, thereby enabling further rounds of matrix protein import, whereas Ubc4p-catalysed polyubiquitination targets Pex5p to proteasomal degradation.

scholarly journals Peroxisome Biogenesis Occurs in an Unsynchronized Manner in Close Association with the Endoplasmic Reticulum in Temperature-sensitiveYarrowia lipolyticaPex3p Mutants

2003 ◽  
Vol 14 (3) ◽  
pp. 939-957 ◽  
Author(s):  
Roger A. Bascom ◽  
Honey Chan ◽  
Richard A. Rachubinski
Keyword(s):  
Endoplasmic Reticulum ◽  
Matrix Protein ◽  
De Novo ◽  
Close Association ◽  
Integral Membrane Protein ◽  
Matrix Proteins ◽  
Temperature Sensitive ◽  
Tubular Structures ◽  
Peroxisome Biogenesis

Pex3p is a peroxisomal integral membrane protein required early in peroxisome biogenesis, and Pex3p-deficient cells lack identifiable peroxisomes. Two temperature-sensitive pex3 mutant strains of the yeast Yarrowia lipolytica were made to investigate the role of Pex3p in the early stages of peroxisome biogenesis. In glucose medium at 16°C, these mutants underwent de novo peroxisome biogenesis and exhibited early matrix protein sequestration into peroxisome-like structures found at the endoplasmic reticulum-rich periphery of cells or sometimes associated with nuclei. The de novo peroxisome biogenesis seemed unsynchronized, with peroxisomes occurring at different stages of development both within cells and between cells. Cells with peripheral nascent peroxisomes and cells with structures morphologically distinct from peroxisomes, such as semi/circular tubular structures that immunostained with antibodies to peroxisomal matrix proteins and to the endoplasmic reticulum-resident protein Kar2p, and that surrounded lipid droplets, were observed during up-regulation of peroxisome biogenesis in cells incubated in oleic acid medium at 16°C. These structures were not detected in wild-type or Pex3p-deficient cells. Their role in peroxisome biogenesis remains unclear. Targeting of peroxisomal matrix proteins to these structures suggests that Pex3p directly or indirectly sequesters components of the peroxisome biogenesis machinery. Such a role is consistent with Pex3p overexpression producing cells with fewer, larger, and clustered peroxisomes.

Sign in / Sign up

Export Citation Format

Share Document