scholarly journals Mitophagy is induced by short ubiquitin chains on mitochondria

2020 ◽  
Vol 219 (9) ◽  
Author(s):  
Fumiyo Ikeda
Keyword(s):  
Membrane Protein ◽  
Critical Role ◽  
Cellular Homeostasis ◽  
Cell Biol ◽  
Novel Complex

Mitophagy has a critical role in maintaining cellular homeostasis by removing damaged mitochondria. In this issue, Yamano et al. (2020. J. Cell Biol. https://doi.org/10.1083/jcb.201912144) uncover that a novel complex of the autophagy adaptor optineurin and the membrane protein ATG9A specifically regulate ubiquitin-induced mitophagy.

A critical role for vesicle-associated membrane protein-7 in exocytosis from human eosinophils and neutrophils

Allergy ◽  
2006 ◽  
Vol 61 (6) ◽  
pp. 777-784 ◽  
Author(s):  
M. R. Logan ◽  
P. Lacy ◽  
S. O. Odemuyiwa ◽  
M. Steward ◽  
F. Davoine ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Critical Role

scholarly journals Incredibly close—A newly identified peroxisome–ER contact site in humans

2017 ◽  
Vol 216 (2) ◽  
pp. 287-289 ◽  
Author(s):  
Maya Schuldiner ◽  
Einat Zalckvar
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Protein ◽  
Binding Protein ◽  
Human Cells ◽  
Metabolic Processes ◽  
Contact Site ◽  
Cell Biol ◽  
Associated Proteins

Peroxisomes are tiny organelles that control important and diverse metabolic processes via their interplay with other organelles, including the endoplasmic reticulum (ER). In this issue, Costello et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201607055) and Hua et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201608128) identify a peroxisome–ER contact site in human cells held together by a tethering complex of VAPA/B (vesicle-associated membrane protein–associated proteins A/B) and ACBD5 (acyl Co-A binding protein 5).

scholarly journals Vid24p, a Novel Protein Localized to the Fructose-1,6-bisphosphatase–containing Vesicles, Regulates Targeting of Fructose-1,6-bisphosphatase from the Vesicles to the Vacuole for Degradation

1998 ◽  
Vol 140 (6) ◽  
pp. 1347-1356 ◽  
Author(s):  
Meng-Chieh Chiang ◽  
Hui-Ling Chiang
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Membrane Protein ◽  
Critical Role ◽  
Carbon Sources ◽  
Degradation Pathway ◽  
Yeast Cells ◽  
Fructose 1,6 Bisphosphatase ◽  
Peripheral Membrane Protein ◽  
Gluconeogenic Enzyme ◽  
Novel Protein

Glucose regulates the degradation of the key gluconeogenic enzyme, fructose-1,6-bisphosphatase (FBPase), in Saccharomyces cerevisiae. FBPase is targeted from the cytosol to a novel type of vesicle, and then to the vacuole for degradation when yeast cells are transferred from medium containing poor carbon sources to fresh glucose. To identify proteins involved in the FBPase degradation pathway, we cloned our first VID (vacuolar import and degradation) gene. The VID24 gene was identified by complementation of the FBPase degradation defect of the vid24-1 mutant. Vid24p is a novel protein of 41 kD and is synthesized in response to glucose. Vid24p is localized to the FBPase-containing vesicles as a peripheral membrane protein. In the absence of functional Vid24p, FBPase accumulates in the vesicles and fails to move to the vacuole, suggesting that Vid24p regulates FBPase targeting from the vesicles to the vacuole. FBPase sequestration into the vesicles is not affected in the vid24-1 mutant, indicating that Vid24p acts after FBPase sequestration into the vesicles has occurred. Vid24p is the first protein identified that marks the FBPase-containing vesicles and plays a critical role in delivering FBPase from the vesicles to the vacuole for degradation.

scholarly journals A Cold-Sensitive Listeria monocytogenes Mutant Has a Transposon Insertion in a Gene Encoding a Putative Membrane Protein and Shows Altered (p)ppGpp Levels

2006 ◽  
Vol 72 (6) ◽  
pp. 3955-3959 ◽  
Author(s):  
Siqing Liu ◽  
Darrell O. Bayles ◽  
Tricia M. Mason ◽  
Brian J. Wilkinson
Keyword(s):  
Listeria Monocytogenes ◽  
Low Temperature ◽  
Membrane Protein ◽  
Transmembrane Domain ◽  
Critical Role ◽  
Peptide Sequence ◽  
Temperature Adaptation ◽  
Signal Peptide Sequence ◽  
C Terminus ◽  
Cold Sensitive

ABSTRACT A cold-sensitive Listeria monocytogenes mutant designated cld-14 was obtained by transposon Tn917 mutagenesis. The gene interrupted by Tn917 in cld-14 was the L. monocytogenes LMOf2365_1485 homolog, which exhibits 45.7% homology to the Bacillus subtilis yqfF locus. LMOf2365_1485, here designated pgpH, encodes a putative integral membrane protein with a predicted molecular mass of 81 kDa. PgpH is predicted to contain a conserved N-terminal signal peptide sequence, seven transmembrane helices, and a hydrophilic C terminus, which likely extends into the cytosol. The Tn917 insertion in pgpH is predicted to result in production of a premature polypeptide truncated at the fifth transmembrane domain. The C terminus of PgpH, which is probably absent in cld-14, contains a highly conserved HD domain that belongs to a metal-dependent phosphohydrolase family. Strain cld-14 accumulated higher levels of (p)ppGpp than the wild type accumulated, indicating that the function of PgpH may be to adjust cellular (p)ppGpp levels during low-temperature growth. The cld-14pgpH + complemented strain was able to grow at a low temperature, like the parent strain, providing direct evidence that the activity of PgpH is important in low-temperature adaptation. Because of its predicted membrane location, PgpH may play a critical role in sensing the environmental temperature and altering cellular (p)ppGpp levels to allow the organism to adapt to low temperatures.

scholarly journals The essential inner membrane protein YejM is a metalloenzyme

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Uma Gabale ◽  
Perla Arianna Peña Palomino ◽  
HyunAh Kim ◽  
Wenya Chen ◽  
Susanne Ressl
Keyword(s):  
Antibiotic Resistance ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Critical Role ◽  
Membrane Properties ◽  
Gram Negative Bacteria ◽  
Inner Membrane ◽  
Gram Negative ◽  
Periplasmic Domain ◽  
Inner Membrane Protein

Abstract Recent recurrent outbreaks of Gram-negative bacteria show the critical need to target essential bacterial mechanisms to fight the increase of antibiotic resistance. Pathogenic Gram-negative bacteria have developed several strategies to protect themselves against the host immune response and antibiotics. One such strategy is to remodel the outer membrane where several genes are involved. yejM was discovered as an essential gene in E. coli and S. typhimurium that plays a critical role in their virulence by changing the outer membrane permeability. How the inner membrane protein YejM with its periplasmic domain changes membrane properties remains unknown. Despite overwhelming structural similarity between the periplasmic domains of two YejM homologues with hydrolases like arylsulfatases, no enzymatic activity has been previously reported for YejM. Our studies reveal an intact active site with bound metal ions in the structure of YejM periplasmic domain. Furthermore, we show that YejM has a phosphatase activity that is dependent on the presence of magnesium ions and is linked to its function of regulating outer membrane properties. Understanding the molecular mechanism by which YejM is involved in outer membrane remodeling will help to identify a new drug target in the fight against the increased antibiotic resistance.

scholarly journals ULK1 cycling: The ups and downs of the autophagy response

2016 ◽  
Vol 215 (6) ◽  
pp. 757-759 ◽  
Author(s):  
Yan G. Zhao ◽  
Hong Zhang
Keyword(s):  
Protein Synthesis ◽  
De Novo ◽  
Proteasomal Degradation ◽  
Nutrient Starvation ◽  
Cellular Homeostasis ◽  
Prolonged Starvation ◽  
Cell Biol ◽  
De Novo Protein Synthesis ◽  
Starvation Conditions

The Ser/Thr kinase ULK1/Atg1 controls autophagy initiation under nutrient starvation conditions. In this issue, Nazio et al. (2016. J. Cell Biol. https://doi.org/10.1083/jcb.201605089) demonstrate that oscillatory modulation of NEDD4L-mediated proteasomal degradation and mTOR-dependent de novo protein synthesis of ULK1 ensures the proper amplitude and duration of the autophagy response during prolonged starvation, thus maintaining cellular homeostasis.

scholarly journals Cell-mediated extracellular acidification and bone resorption: evidence for a low pH in resorbing lacunae and localization of a 100-kD lysosomal membrane protein at the osteoclast ruffled border.

1985 ◽  
Vol 101 (6) ◽  
pp. 2210-2222 ◽  
Author(s):  
R Baron ◽  
L Neff ◽  
D Louvard ◽  
P J Courtoy
Keyword(s):  
Bone Resorption ◽  
Membrane Protein ◽  
Ammonium Chloride ◽  
Bone Matrix ◽  
Low Ph ◽  
Lysosomal Membrane ◽  
Cell Biol ◽  
Extracellular Compartment ◽  
Ruffled Border ◽  
Lysosomal Membrane Protein

The extracellular compartment where bone resorption occurs, between the osteoclast and bone matrix, is shown in this report to be actively acidified. The weak base acridine orange accumulates within this compartment but dissipates after incubation with ammonium chloride. Upon removal of ammonium chloride, the cells are able to rapidly reacidify this compartment. The highly convoluted plasma membrane of the osteoclast facing this acidic compartment (ruffled border) is shown to contain a 100-kD integral membrane protein otherwise present in limiting membranes of lysosomes and other related acidified organelles (Reggio, H., D. Bainton, E. Harms, E. Coudrier, and D. Louvard, 1984, J. Cell Biol., 99:1511-1526; Tougard, C., D. Louvard, R. Picart, and A. Tixier-Vidal, 1985, J. Cell Biol. 100:786-793). Antibodies recognizing this 100-kD lysosomal membrane protein cross-react with a proton-pump ATPase from pig gastric mucosae (Reggio, H., D. Bainton, E. Harms, E. Coudrier, and D. Louvard, 1984, J. Cell Biol., 99:1511-1526), therefore raising the possibility that it plays a role in the acidification of both intracellular organelles and extracellular compartments. Lysosomal enzymes are also directionally secreted by the osteoclast into the acidified extracellular compartment which can therefore be considered as the functional equivalent of a secondary lysosome with a low pH, acid hydrolases, the substrate, and a limiting membrane containing the 100-kD antigen.

Mechanisms of mitophagy: putting the powerhouse into the doghouse

2016 ◽  
Vol 397 (7) ◽  
pp. 617-635 ◽  
Author(s):  
Joel S. Riley ◽  
Stephen W.G. Tait
Keyword(s):  
Cell Death ◽  
Critical Role ◽  
Cellular Homeostasis ◽  
Therapeutic Benefits ◽  
Calcium Storage ◽  
Endosymbiotic Event ◽  
A Cell ◽  
The Impact

Abstract Since entering our cells in an endosymbiotic event one billion years ago, mitochondria have shaped roles for themselves in metabolism, inflammation, calcium storage, migration, and cell death. Given this critical role in cellular homeostasis it is essential that they function correctly. Equally critical is the ability of a cell to remove damaged or superfluous mitochondria to avoid potential deleterious effects. In this review we will discuss the various mechanisms of mitochondrial clearance, with a particular focus on Parkin/PINK1-mediated mitophagy, discuss the impact of altered mitophagy in ageing and disease, and finally consider potential therapeutic benefits of targeting mitophagy.

scholarly journals Dissociating morphological and form priming with novel complex word primes

2015 ◽  
Vol 10 (3) ◽  
pp. 413-434 ◽  
Author(s):  
Robert Fiorentino ◽  
Stephen Politzer-Ahles ◽  
Natalie S. Pak ◽  
María Teresa Martínez-García ◽  
Caitlin Coughlin
Keyword(s):  
Critical Role ◽  
Reaction Times ◽  
Masked Priming ◽  
Priming Effects ◽  
Lexical Status ◽  
Morphological Priming ◽  
Novel Complex ◽  
Complex Words ◽  
Orthographic Priming

Recent research suggests that visually-presented words are initially morphologically segmented whenever the letter-string can be exhaustively assigned to existing morphological representations, but not when an exhaustive parse is unavailable; e.g., priming is observed for both hunter → HUNT and brother → BROTH, but not for brothel → BROTH. Few studies have investigated whether this pattern extends to novel complex words, and the results to date (all from novel suffixed words) are mixed. In the current study, we examine whether novel compounds (drugrack → RACK) yield morphological priming which is dissociable from that in novel pseudoembedded words (slegrack → RACK). Using masked priming, we find significant and comparable priming in reaction times for word-final elements of both novel compounds and novel pseudoembedded words. Using overt priming, however, we find greater priming effects (in both reaction times and N400 amplitudes) for novel compounds compared to novel pseudoembedded words. These results are consistent with models assuming across-the-board activation of putative constituents, while also suggesting that morpheme activation may persevere despite the lack of an exhaustive morpheme-based parse when an exhaustive monomorphemic analysis is also unavailable. These findings highlight the critical role of the lexical status of the pseudoembedded prime in dissociating morphological and orthographic priming.

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