Shedding of cytoplasmic actins by developing muscle cells

1988 ◽  
Vol 89 (2) ◽  
pp. 273-282
Author(s):  
G.M. Denning ◽  
I.S. Kim ◽  
A.B. Fulton
Keyword(s):  
Protein Synthesis ◽  
Electron Microscope ◽  
Culture Medium ◽  
Muscle Cells ◽  
Cytoskeletal Proteins ◽  
Inhibit Protein Synthesis ◽  
Culture Dish ◽  
Cytoplasmic Actin ◽  
Alpha Actin ◽  
Developing Muscle

Young myotubes develop spots or macules of actin and alpha actinin under and adjacent to slender actin strands. Macules are found only before sarcomere formation. They contain cytoplasmic actin, small amounts of alpha actin, and alpha actinin but are devoid of tubulin, myosin and vimentin. In the electron microscope, they are seen to contain small filaments but no other organelles. Macules are found on the culture dish and in the culture medium, as well as on the lower and lateral surfaces of the cells. Both emetine and cycloheximide, at doses that inhibit protein synthesis, accelerate formation and shedding of macules. This presents the first observation of a cellular system in which the changeover from a generalized cytoskeleton to a tissue-specific cytoskeleton involves shedding of the cytoplasmic isoforms of cytoskeletal proteins.

Stimulation of actin synthesis by cytochalasin D is specific for the isoactins normally expressed in muscle or non-muscle cells

1986 ◽  
Vol 84 (1) ◽  
pp. 253-262
Author(s):  
J. Tannenbaum ◽  
A.F. Miranda
Keyword(s):  
Muscle Cell ◽  
Cell Cultures ◽  
Muscle Cells ◽  
Cytochalasin D ◽  
Human Muscle ◽  
The State ◽  
Cytoskeletal Proteins ◽  
Developmentally Regulated ◽  
Alpha Actin ◽  
Stimulation Of

Treatment of human muscle myotube cultures with 2 microM-cytochalasin D (CD) for 6 h stimulated synthesis of both the (muscle-specific) alpha-actin and the (non-muscle) beta and gamma-actins usually expressed by these cells. In non-muscle (HEp-2) cell cultures, CD enhanced synthesis of beta and gamma-actin, but did not induce synthesis of alpha-actin, which is not normally present in these cells. Thus, synthesis of both muscle and non-muscle actins can be increased by CD, but enhancement of actin synthesis results from increases in the isoactins usually present, rather than induction of new isotypes. Comparison of CD-treated (fused) myotube cultures with (unfused) myoblast cultures indicated that beta and gamma-actin synthesis was similarly enhanced in both cultures, but that alpha-actin synthesis was stimulated to a greater extent in the myoblast cultures. Desmin synthesis was also stimulated in the myoblasts but not the myotubes, suggesting that the effect of CD on synthesis of these developmentally regulated cytoskeletal proteins (alpha-actin, desmin) might be modulated by fusion or the state of differentiation of the muscle cell.

scholarly journals DIFFERENTIATION OF THE SARCOPLASMIC RETICULUM AND T SYSTEM IN DEVELOPING CHICK SKELETAL MUSCLE IN VITRO

1967 ◽  
Vol 35 (2) ◽  
pp. 405-420 ◽  
Author(s):  
Elizabeth B. Ezerman ◽  
Harunori Ishikawa
Keyword(s):  
Skeletal Muscle ◽  
Electron Microscope ◽  
Sarcoplasmic Reticulum ◽  
Osmium Tetroxide ◽  
Muscle Cells ◽  
Simultaneous Occurrence ◽  
Chick Embryos ◽  
Developing Muscle ◽  
T System

The electron microscope was used to investigate the first 10 days of differentiation of the SR and the T system in skeletal muscle cultured from the breast muscle of 11-day chick embryos. The T-system tubules could be clearly distinguished from the SR in developing muscle cells fixed with glutaraldehyde and osmium tetroxide. Ferritin diffusion confirmed this finding: the ferritin particles were found only in the tubules identified as T system. The proliferation of both membranous systems seemed to start almost simultaneously at the earliest myotube stage. Observations suggested that the new SR membranes developed from the rough-surfaced ER as tubular projections. The SR tubules connected with one another to form a network around the myofibril. The T-system tubules were formed by invagination of the sarcolemma. The early extension of the T system by branching and budding was seen only in subsarcolemmal regions. Subsequently the T-system tubules could be seen deep within the muscle cells. Immediately after invaginating, the T-system tubule formed, along its course, specialized connections with the SR or ER: triadic structures showing various degrees of differentiation. The simultaneous occurrence of myofibril formation and membrane proliferation is considered to be important in understanding the coordinated events resulting in the differentiated myotube.

scholarly journals SUPPRESSION OF DELAYED HYPERSENSITIVITY IN VITRO BY INHIBITION OF PROTEIN SYNTHESIS

1965 ◽  
Vol 122 (6) ◽  
pp. 1125-1134 ◽  
Author(s):  
John R. David
Keyword(s):  
Protein Synthesis ◽  
Culture Medium ◽  
Specific Antigen ◽  
Delayed Hypersensitivity ◽  
Cell Protein ◽  
Sensitive Cell ◽  
Active Protein ◽  
Inhibit Protein Synthesis ◽  
Inhibition Of Protein Synthesis

Peritoneal cells from guinea pigs exhibiting delayed hypersensitivity are inhibited from migrating in vitro by specific antigen. This inhibition is prevented by the addition of puromycin to the culture medium. The amount of puromycin necessary to prevent the inhibition by antigen also suppressed the incorporation of C14-leucine into peritoneal cell protein. Additional evidence that the action of puromycin is due to its inhibition of protein synthesis has been obtained with analogues of puromycin; those that inhibit protein synthesis also prevent the action of antigen on the cells, while those analogues that do not inhibit protein synthesis have no effect. Actinomycin also prevents the inhibition of sensitive cells by antigen while chloramphenicol has no effect. The data indicate that the inhibition of sensitive cell migration by antigen requires active protein synthesis. The possible mechanisms by which inhibition of protein synthesis may influence the in vitro reactions of delayed hypersensitivity are discussed.

scholarly journals The Effects of ZnO Nanoparticles in Combination with Alcohol on Biosynthetic Potential of Saccharomyces cerevisiae

2017 ◽  
Vol 21 (2) ◽  
pp. 19-24
Author(s):  
Natalia Chiseliţa ◽  
Agafia Usatii ◽  
Nadejda Efremova
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Synthesis ◽  
Enzyme Activity ◽  
Biomass Production ◽  
Zno Nanoparticles ◽  
Yeast Strain ◽  
Culture Medium ◽  
Inhibit Protein Synthesis ◽  
Maximum Value ◽  
Directed Synthesis

Abstract This paper reports about experimental results concerning the influence of 30 nm ZnO nanoparticles on biomass, carbohydrates, β-glucans, proteins accumulation and catalase enzyme activity at Saccharomyces cerevisiae CNMN-Y-20 yeast strain exposed to alcohol action. Alcohol in concentrations of 2%, 5% and 10% added to culture medium has been reported to stimulate β-glucans biosynthesis and to inhibit protein synthesis. Low biomass production, with 71% less that control, was detected in the experiments with 10% alcohol. ZnO nanoparticles in combination with alcohol do not offer sufficient protection for the proteins biosynthesis, but efficiently protect the carbohydrates and β-glucans biosynthetic processes, which contents in the biomass are with 16.6% and 19.9% higher than control, respectively. The maximum value of β-glucans content was established in case of cultivation of selected yeast strain on YPD medium supplemented with 5 mg/L nanoparticles ZnO and 2% alcohol. The obtained results allowed the elaboration of new procedure for directed synthesis of β-glucans that contributed to an increase of this component with 30.7%, compared to control.

INHIBITION OF THYROGLOBULIN BIOSYNTHESIS AND DEGRADATION BY EXCESS IODIDE. SYNERGISM WITH LITHIUM

1976 ◽  
Vol 81 (2) ◽  
pp. 495-506 ◽  
Author(s):  
A. Radvila ◽  
R. Roost ◽  
H. Bürgi ◽  
H. Kohler ◽  
H. Studer
Keyword(s):  
Protein Synthesis ◽  
Thyroid Gland ◽  
Inhibitory Action ◽  
Inhibit Protein Synthesis ◽  
Thyrotrophic Hormone ◽  
Thyroid Glands ◽  
Pre Treatment ◽  
Excess Iodide ◽  
Kidney Liver

ABSTRACT Lithium and excess iodide inhibit the release of thyroid hormone from preformed stores. We thus tested the hypothesis that this was due to an inhibition of thyroglobulin breakdown. Rats were pre-treated with propylthiouracil (PTU) for 3 weeks in order to deplete their thyroids of thyroglobulin. While the PTU was continued, lithium chloride (0.25 mEq./100 g weight) or potassium iodide (3 mg per rat) were injected every 12 h for 3 days. Thereafter the thyroglobulin content in thyroid gland homogenates was measured. PTU pre-treatment lowered the thyroglobulin content from 4.21 to 0.22 mg/100 mg gland. Lithium caused a marked re-accumulation of thyroglobulin to 0.60 mg/100 mg within 3 days. While iodide alone had only a borderline effect, it markedly potentiated the action of lithium and a combination of the two drugs increased the thyroglobulin content to 1.04 mg/100 mg. Thyroxine was injected into similarly pre-treated animals to suppress secretion of thyrotrophic hormone. This markedly inhibited the proteolysis of thyroglobulin and 1.3 mg/100 mg gland accumulated after 3 days. Excess iodide, given in addition to thyroxine, decreased the amount of thyroglobulin accumulated to 0.75 mg/100 mg gland. To study whether this could be explained by an inhibitory action of iodide on thyroglobulin biosynthesis, thyroid glands from animals treated with excess iodide were incubated in vitro in the presence of 0.2 mm iodide for 3 h. Iodide decreased the incorporation of radioactive leucine into total thyroidal protein and into thyroglobulin by 25 and 35 % respectively. Iodide did not inhibit protein synthesis in the kidney, liver or muscle tissue. Thus, large doses of iodide selectively inhibit thyroglobulin biosynthesis.

Ceramide down‐regulates System A amino acid transport and protein synthesis in rat skeletal muscle cells

2004 ◽  
Vol 19 (3) ◽  
pp. 1-24 ◽  
Author(s):  
Russell Hyde ◽  
Eric Hajduch ◽  
Darren J. Powell ◽  
Peter M. Taylor ◽  
Harinder S. Hundal
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Acid Transport ◽  
Rat Skeletal Muscle ◽  
System A

Cytoskeletal proteins associate with components of the ribosomal maturation and translation apparatus in Xenopus stage I oocytes

Zygote ◽  
2014 ◽  
Vol 23 (5) ◽  
pp. 669-682 ◽  
Author(s):  
Loredana Chierchia ◽  
Margherita Tussellino ◽  
Domenico Guarino ◽  
Rosa Carotenuto ◽  
Nadia DeMarco ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Elongation Factor ◽  
Cytoskeletal Proteins ◽  
Stage I ◽  
Initiation Factor ◽  
Perinuclear Region ◽  
Eukaryotic Initiation Factor ◽  
Translation Apparatus ◽  
Ribosomal Stalk

SummaryActin-based cytoskeleton (CSK) and microtubules may bind to RNAs and related molecules implicated in translation. However, many questions remain to be answered regarding the role of cytoskeletal components in supporting the proteins involved in steps in the maturation and translation processes. Here, we performed co-immunoprecipitation and immunofluorescence to examine the association between spectrins, keratins and tubulin and proteins involved in 60S ribosomal maturation and translation in Xenopus stage I oocytes, including ribosomal rpl10, eukaryotic initiation factor 6 (Eif6), thesaurins A/B, homologs of the eEF1α elongation factor, and P0, the ribosomal stalk protein. We found that rpl10 and eif6 cross-reacted with the actin-based CSK and with tubulin. rpl10 co-localizes with spectrin, particularly in the perinuclear region. eif6 is similarly localized. Given that upon ribosomal maturation, the insertion of rpl10 into the 60S subunit occurs simultaneously with the release of eif6, one can hypothesise that actin-based CSK and microtubules provide the necessary scaffold for the insertion/release of these two molecules and, subsequently, for eif6 transport and binding to the mature 60S subunit. P0 and thesaurins cross-reacted with only spectrin and cytokeratins. Thesaurins aggregated at the oocyte periphery, rendering this a territory favourable site for protein synthesis; the CSK may support the interaction between thesaurins and sites of the translating ribosome. Moreover, given that the assembly of the ribosome stalk, where P0 is located, to the 60S subunit is essential for the release of eif6, it can be hypothesised that the CSK can facilitate the binding of the stalk to the 60S.

scholarly journals Association of beta-cytoplasmic actin with high concentrations of acetylcholine receptor (AChR) in normal and anti-AChR-treated primary rat muscle cultures.

1984 ◽  
Vol 32 (9) ◽  
pp. 973-981 ◽  
Author(s):  
B W Lubit
Keyword(s):  
Acetylcholine Receptor ◽  
Acetylcholine Receptors ◽  
Neuromuscular Junctions ◽  
Morphological Changes ◽  
Muscle Cells ◽  
High Concentration ◽  
Rat Muscle ◽  
Cytoplasmic Actin ◽  
High Concentrations

Previous immunocytochemical studies in which an antibody specific for mammalian cytoplasmic actin was used showed that a high concentration of cytoplasmic actin exists at neuromuscular junctions of rat muscle fibers such that the distribution of actin corresponded exactly to that of the acetylcholine receptors. Although clusters of acetylcholine receptors also are present in noninnervated rat and chick muscle cells grown in vitro, neither the mechanism for the formation and maintenance of these clusters nor the relationship of these clusters to the high density of acetylcholine receptors at the neuromuscular junction in vivo are known. In the present study, a relationship between beta-cytoplasmic actin and acetylcholine receptors in vitro has been demonstrated immunocytochemically using an antibody specific for the beta-form of cytoplasmic actin. Networks of cytoplasmic actin-containing filaments were found in discrete regions of the myotube membrane that also contained high concentrations of acetylcholine receptors; such high concentrations of acetylcholine receptors have been described in regions of membrane-substrate contact. Moreover, when primary rat myotubes were exposed to human myasthenic serum, gross morphological changes, accompanied by an apparent rearrangement of the cytoplasmic actin-containing cytoskeleton, were produced. Although whether the distribution of cytoplasmic actin-containing structures was influenced by the organization of acetylcholine receptor or vice versa cannot be determined from these studies, these findings suggest that in primary rat muscle cells grown in vitro, acetylcholine receptors and beta-cytoplasmic actin-containing structures may be somehow connected.

Altered Cytoskeleton in Smooth Muscle of Aganglionic Bowel

2002 ◽  
Vol 126 (6) ◽  
pp. 692-696
Author(s):  
Laszlo Nemeth ◽  
Udo Rolle ◽  
Prem Puri
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Laser Scanning ◽  
Hirschsprung Disease ◽  
Muscle Cells ◽  
Cytoskeletal Proteins ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Normal Bowel ◽  
Pull Through

Abstract Context.—Intestinal motility is under the control of smooth muscle cells, enteric plexus, and hormonal factors. In Hirschsprung disease (HD), the aganglionic colon remains spastic or tonically enhanced and unable to relax. The smooth muscle cell's cytoskeleton consists of proteins or structures whose primary function is to link or connect protein filaments to each other or to the anchoring sites. Dystrophin is a subsarcolemmal protein with a double adhesion property, one between the membrane elements and the contractile filaments of the cytoskeleton and the other between the cytoskeletal proteins and the extracellular matrix. Desmin and vinculin are functionally related proteins that are present in the membrane-associated dense bodies in the sarcolemma of the smooth muscle cells. Objective.—To examine the distribution of the cytoskeletal proteins in the smooth muscle of the aganglionic bowel. Design.—Bowel specimens from ganglionic and aganglionic sections of the colon were collected at the time of pull-through surgery from 8 patients with HD. Colon specimens collected from 4 patients at the time of bladder augmentation acted as controls. Anti-dystrophin, anti-desmin, and anti-vinculin antibodies were used for fluorescein immunostaining using confocal laser scanning microscopy. Results.—Moderate to strong dystrophin immunoreactivity was observed at the periphery of smooth muscle fibers in normal bowel and ganglionic bowel from patients with HD, whereas dystrophin immunoreactivity was either absent or weak in the smooth muscle of aganglionic colon. Moderate to strong cytoplasmic immunostaining for vinculin and desmin was seen in the smooth muscle of normal bowel and ganglionic bowel from patients with HD, whereas vinculin and desmin staining in the aganglionic colon was absent or weak. Conclusion.—This study demonstrates that the cytoskeletal proteins are abundant in the smooth muscle of normal bowel, but are absent or markedly reduced in the aganglionic bowel of HD. As cytoskeletal proteins are required for the coordinated contraction of muscle cells, their absence may be responsible for the motility dysfunction in the aganglionic segment.

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