scholarly journals Ciliogenesis‐coupled accumulation of IFT‐B proteins in a novel cytoplasmic compartment

2019 ◽  
Vol 24 (11) ◽  
pp. 731-745 ◽  
Author(s):  
Lynda Lamri ◽  
Wang Kyaw Twan ◽  
Takanobu A. Katoh ◽  
Yanick Botilde ◽  
Katsuyoshi Takaoka ◽  
...  
Keyword(s):  
Cytoplasmic Compartment

Limitations of Allotopic Expression of Mitochondrial Genes in Mammalian Cells

Genetics ◽  
2003 ◽  
Vol 165 (2) ◽  
pp. 707-720
Author(s):  
Jose Oca-Cossio ◽  
Lesley Kenyon ◽  
Huiling Hao ◽  
Carlos T Moraes
Keyword(s):  
Mitochondrial Dna ◽  
Mammalian Cells ◽  
Mitochondrial Genes ◽  
Terminal Segment ◽  
Universal Genetic Code ◽  
Apocytochrome B ◽  
Dna Mutations ◽  
C Terminus ◽  
Cytoplasmic Compartment ◽  
Allotopic Expression

Abstract The possibility of expressing mitochondrial DNA-coded genes in the nuclear-cytoplasmic compartment provides an attractive system for genetic treatment of mitochondrial disorders associated with mitochondrial DNA mutations. In theory, by recoding mitochondrial genes to adapt them to the universal genetic code and by adding a DNA sequence coding for a mitochondrial-targeting sequence, one could achieve correct localization of the gene product. Such transfer has occurred in nature, and certain species of algae and plants express a number of polypeptides that are commonly coded by mtDNA in the nuclear-cytoplasmic compartment. In the present study, allotopic expression of three different mtDNA-coded polypeptides (ATPase8, apocytochrome b, and ND4) into COS-7 and HeLa cells was analyzed. Among these, only ATPase8 was correctly expressed and localized to mitochondria. The full-length, as well as truncated forms, of apocytochrome b and ND4 decorated the periphery of mitochondria, but also aggregated in fiber-like structures containing tubulin and in some cases also vimentin. The addition of a hydrophilic tail (EGFP) to the C terminus of these polypeptides did not change their localization. Overexpression of molecular chaperones also did not have a significant effect in preventing aggregations. Allotopic expression of apocytochrome b and ND4 induced a loss of mitochondrial membrane potential in transfected cells, which can lead to cell death. Our observations suggest that only a subset of mitochondrial genes can be replaced allotopically. Analyses of the hydrophobic patterns of different polypeptides suggest that hydrophobicity of the N-terminal segment is the main determinant for the importability of peptides into mammalian mitochondria.

Development of Ca2+ homeostasis in epithelial cells from embryonic and neonatal intestine

1992 ◽  
Vol 263 (3) ◽  
pp. G371-G379
Author(s):  
B. L. Black ◽  
J. O. Rogers
Keyword(s):  
Alkaline Phosphatase ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Fluorescent Probe ◽  
Cell Suspensions ◽  
Fura 2 ◽  
Alp Activity ◽  
High Viability ◽  
Cytoplasmic Compartment ◽  
Highly Correlated

The fluorescent probe fura-2 was used to assay Ca2+ levels in epithelial cell suspensions from embryonic and neonatal chick duodenum. Cell preparations maintained high viability, completely hydrolyzed fura-2/AM to fura-2, retained 92% of cellular fura-2 within the cytoplasmic compartment, and gave low autofluorescence values during assay. Fura-2 leakage from loaded cells occurred at all ages, but could be corrected for in subsequent calculations of cellular Ca2+. Cytoplasmic Ca2+ concentration was 76-80 nM in cells from 14- to 16-day embryonic intestine, rose significantly to 92-98 nM at 17-20 days, and reached 209 nM at 1-day post-hatch when assayed in buffers containing 1.3 mM Ca2+. The developmental rise in cytoplasmic Ca2+ was accompanied by an enhanced ability of cells to maintain a constant Ca2+ concentration at increased levels of extracellular Ca2+ and by a highly correlated rise in alkaline phosphatase (ALP) activity. Epithelial Ca2+ subsequently decreased to the "adult" value of 133-142 nM and was constant along the crypt-villus axis of neonatal intestine. These results verify that fura-2 can be used to compare baseline cytoplasmic Ca2+ values of epithelial cells from developing intestine, reveal that significant changes in Ca2+ homeostasis occur during ontogeny, and suggest that epithelial Ca2+ may modulate ALP activity during the differentiation of embryonic enterocytes.

Depletion and filling of intracellular calcium stores in vascular smooth muscle

1995 ◽  
Vol 268 (2) ◽  
pp. C503-C512 ◽  
Author(s):  
L. A. Blatter
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Surface Membrane ◽  
Membrane Receptors ◽  
Calcium Stores ◽  
Fura 2 ◽  
Vasoactive Substances ◽  
Cytoplasmic Compartment ◽  
A7r5 Cell Line ◽  
Cellular Compartments

In vascular smooth muscle, binding of vasoactive substances to surface membrane receptors leads to a rise of intracellular cytoplasmic Ca2+ and to contraction. Cytoplasmic free Ca2+ concentration ([Ca2+]i) increases through release of Ca2+ from intracellular stores and Ca2+ entry through surface membrane ion channels. Membrane-permeant and membrane-impermeant forms of fura 2 were used to distinguish changes in intracellularly stored Ca2+ ([Ca2+]s) from changes in [Ca2+]i. The spatiotemporal patterns of the movement of Ca2+ between these two cellular compartments in cultured vascular smooth muscle cells (A7r5 cell line) were visualized with digital imaging fluorescence microscopy. The Ca2+ stores were localized by double staining with a fluorescent organelle-specific dye and the Ca2+ indicator. [Ca2+]s was measured after accumulation of the membrane-permeant form of fura 2 inside the stores and quenching of the fura 2 fluorescence in the cytoplasmic compartment with manganese. Stimulation with vasopressin led to a transient increase of [Ca2+]i and a concomitant decrease of [Ca2+]s. After stimulation with vasopressin, [Ca2+]i returned rapidly to normal resting levels, whereas the recovery of [Ca2+]s occurred on a much slower time scale. The refilling pathway of depleted stores involved Ca2+ entry into the bulk cytoplasmic compartment before uptake into the stores.

scholarly journals Transport of a fluorescent macromolecule via endosomes to the vacuole in Saccharomyces cerevisiae.

1987 ◽  
Vol 104 (1) ◽  
pp. 67-75 ◽  
Author(s):  
M Makarow ◽  
L T Nevalainen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ammonium Chloride ◽  
Mammalian Cells ◽  
Extracellular Fluid ◽  
Endocytic Pathway ◽  
Sodium Vanadate ◽  
Energy Depletion ◽  
Internal Ph ◽  
Intermediate Compartment ◽  
Cytoplasmic Compartment

Fluorescein isothiocyanate-conjugated dextran (FITC-dextran) is internalized by endocytosis into the lysosome-like vacuoles of Saccharomyces cerevisiae (Makarow, M., 1985, EMBO (Eur. Mol. Biol. Organ.) J. 4:1861-1866). Here we show that under energy depletion conditions FITC-dextran accumulated in a cytoplasmic compartment, from which it could be chased to the vacuole when the energy block was removed. The internal pH of the intermediate compartment under energy depletion was determined by fluorometry to be 5.8. The pH could be raised by the lysosomotropic agent ammonium chloride, the protonophore carbonyl cyanide p-trifluoromethoxyphenyl-hydrazone (CCCP) and the ATPase inhibitors dicyclohexylcarbodiimide (DCCD) and sodium vanadate. The pH of the vacuole was found to be 6.5. It was raised by ammonium chloride, CCCP, and DCCD, but not with sodium vanadate. Efrapeptin had no effect on the internal pH of either compartment. By dissecting the endocytic pathway, two portions of the route leading to the vacuole could be studied separately. The internalization of FITC-dextran from the extracellular fluid to the intermediate compartment followed linear kinetics, was independent of energy, and occurred at temperatures of between 15 degrees and 37 degrees C. Transfer of the marker from the intermediate compartment to the vacuole required energy, took place at temperatures between 19 degrees and 37 degrees C, and had a half-time of 7 min at 37 degrees C. Transport of the marker from the exterior of the cell to the vacuole did not require acidic pH values in the intermediate compartment or the vacuole. We suggest that the cytoplasmic compartment revealed by FITC-dextran, under energy depletion, represents the equivalent of the endosomes of mammalian cells.

Evidence for several separate functional pools of NAD(H) within the cytoplasmic compartment of the hepatocyte

1980 ◽  
Vol 8 (5) ◽  
pp. 570-570 ◽  
Author(s):  
MICHAEL N. BERRY ◽  
DEBRA C. FANNING ◽  
ANTHONY R. GRIVELL ◽  
SIMON J. LEWIS ◽  
CHRISTINE J. FARRINGTON ◽  
...  
Keyword(s):  
Cytoplasmic Compartment

Apoptosis Is Physiologically Restricted to a Specialized Cytoplasmic Compartment in Rat Spermatids

1999 ◽  
Vol 61 (6) ◽  
pp. 1541-1547 ◽  
Author(s):  
Josefa Blanco-Rodríguez ◽  
Carmen Martínez-García
Keyword(s):  
Cytoplasmic Compartment

scholarly journals Effect of l-Carnitine on Acetyl-CoA Content and Activity of Blood Platelets in Healthy and Diabetic Persons

2005 ◽  
Vol 51 (9) ◽  
pp. 1673-1682 ◽  
Author(s):  
Anna Michno ◽  
Anna Raszeja-Specht ◽  
Agnieszka Jankowska-Kulawy ◽  
Tadeusz Pawełczyk ◽  
Andrzej Szutowicz
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Fatty Acid Synthase ◽  
Blood Platelets ◽  
Vascular Complications ◽  
Diabetic Patients ◽  
Healthy Individuals ◽  
Platelet Activity ◽  
Acetyl Coa ◽  
Cytoplasmic Compartment

Abstract Background: Excessive blood platelet activity contributes to vascular complications in diabetic persons. Increased acetyl-CoA in platelets from diabetic persons has been suggested to be a cause of this hyperactivity. We therefore investigated whether l-carnitine, which up-regulates metabolism of acetyl-CoA in muscles and brain, may affect platelet function in healthy and diabetic individuals. Methods: We obtained platelets from healthy and diabetic persons and measured acetyl-CoA concentrations, malonyl dialdehyde (MDA) synthesis, and platelet aggregation in the absence and presence of l-carnitine. Activities of selected enzymes involved in glucose and acetyl-CoA metabolism were also assessed. Results: Fasting glucose, fructosamine, and hemoglobin A1c were present in significantly higher amounts in the blood of diabetic patients than in healthy individuals. Activities of carnitine acetyltransferase, glucose-6-phosphate dehydrogenase, oxoglutarate dehydrogenase, and fatty acid synthase were 17%–62% higher in platelets from diabetic patients. Mitochondrial acetyl-CoA was increased by 98% in platelets from diabetic patients, MDA synthesis was increased by 73%, and platelet aggregation by 60%. l-Carnitine had no or only a slight effect on these indices in platelets from healthy individuals, but in platelets from diabetic patients, l-carnitine caused a 99% increase in acetyl-CoA in the cytoplasmic compartment along with increases in MDA synthesis and platelet aggregation. Conclusions: Excessive platelet activity in persons with diabetes may result from increased acetyl-CoA, which apparently increases synthesis of lipid activators of platelet function. l-Carnitine may aggravate platelet hyperactivity in diabetic persons by increasing the provision of surplus acetyl-CoA to the cytoplasmic compartment.

scholarly journals Functional compartmentalization and metabolic separation in a prokaryotic cell

2021 ◽  
Vol 118 (25) ◽  
pp. e2022114118
Author(s):  
Jennifer Flechsler ◽  
Thomas Heimerl ◽  
Harald Huber ◽  
Reinhard Rachel ◽  
Ivan A. Berg
Keyword(s):  
Outer Membrane ◽  
Protein Biosynthesis ◽  
Atp Synthesis ◽  
Side Reactions ◽  
Strictly Anaerobic ◽  
Prokaryotic Cell ◽  
Dna And Rna ◽  
Information Processes ◽  
Cytoplasmic Compartment ◽  
Gradient Generation

The prokaryotic cell is traditionally seen as a “bag of enzymes,” yet its organization is much more complex than in this simplified view. By now, various microcompartments encapsulating metabolic enzymes or pathways are known for Bacteria. These microcompartments are usually small, encapsulating and concentrating only a few enzymes, thus protecting the cell from toxic intermediates or preventing unwanted side reactions. The hyperthermophilic, strictly anaerobic Crenarchaeon Ignicoccus hospitalis is an extraordinary organism possessing two membranes, an inner and an energized outer membrane. The outer membrane (termed here outer cytoplasmic membrane) harbors enzymes involved in proton gradient generation and ATP synthesis. These two membranes are separated by an intermembrane compartment, whose function is unknown. Major information processes like DNA replication, RNA synthesis, and protein biosynthesis are located inside the “cytoplasm” or central cytoplasmic compartment. Here, we show by immunogold labeling of ultrathin sections that enzymes involved in autotrophic CO2 assimilation are located in the intermembrane compartment that we name (now) a peripheric cytoplasmic compartment. This separation may protect DNA and RNA from reactive aldehydes arising in the I. hospitalis carbon metabolism. This compartmentalization of metabolic pathways and information processes is unprecedented in the prokaryotic world, representing a unique example of spatiofunctional compartmentalization in the second domain of life.

scholarly journals Chlamydial Effector Proteins Localized to the Host Cell Cytoplasmic Compartment

2008 ◽  
Vol 76 (11) ◽  
pp. 4842-4850 ◽  
Author(s):  
Betsy Kleba ◽  
Richard S. Stephens
Keyword(s):  
Bacterial Pathogens ◽  
Eukaryotic Cell ◽  
Effector Proteins ◽  
Host Cells ◽  
Developmental Cycle ◽  
Secretion Systems ◽  
Bacterial Proteins ◽  
Cell Functions ◽  
Infected Cells ◽  
Cytoplasmic Compartment

ABSTRACT Disease-causing microbes utilize various strategies to modify their environment in order to create a favorable location for growth and survival. Gram-negative bacterial pathogens often use specialized secretion systems to translocate effector proteins directly into the cytosol of the eukaryotic cells they infect. These bacterial proteins are responsible for modulating eukaryotic cell functions. Identification of the bacterial effectors has been a critical step toward understanding the molecular basis for the pathogenesis of the bacteria that use them. Chlamydiae are obligate intracellular bacterial pathogens that have a type III secretion system believed to translocate virulence effector proteins into the cytosol of their host cells. Selective permeabilization of the eukaryotic cell membrane was used in conjunction with metabolic labeling of bacterial proteins to identify chlamydial proteins that localize within the cytosol of infected cells. More than 20 Chlamydia trachomatis and C. pneumoniae proteins were detected within the cytoplasmic compartment of infected cells. While a number of cytosolic proteins were shared, others were unique to each species, suggesting that variation among cytosolic chlamydial proteins contributes to the differences in the pathogenesis of the chlamydial species. The spectrum of chlamydial proteins exported differed concomitant with the progress of the developmental cycle. These data confirm that a dynamic relationship exists between Chlamydia and its host and that translocation of bacterial proteins into the cytosol is developmentally dependent.

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