Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CYTOPLASM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,477 records · Page 82Linked to original sources
PubMed1992

Immunoelectron microscopic localization of antigens which react with islet cell cytoplasmic antibodies within human pancreatic beta cells.

The presence of circulating autoantibody to islet cell cytoplasm is considered to be an important marker of Type 1 (insulin-dependent) diabetes mellitus. In the present study using islet cell cytoplasmic antibody positive patient sera as the first antibody, we studied the intracellular distribution of its antigen at the electron microscopic level using the pre-embedding immunoperoxidase method. Specific immunoreactivity was found in the membranes of beta cell-secretory granules and cytoplasmic membranes. This result is compatible with the interpretation that the antigen(s) on the membranes of beta cell secretory granules is (are) the target of islet cell cytoplasmic antibody.

Autoantibodies↗
PubMed1979

An X-ray microanalysis survey of the concentration of elements in the cytoplasm of different mammalian cell types.

Electron probe energy dispersive X-ray microanalysis was performed on freeze-dried tissue sections. The dry weight concentration of elements (mmole/kg dry weight) was measured in the cytoplasm of several cell types from adult mice and rats. This comparative investigation showed: (1) That the energy dispersive X-ray spectrum of element concentration from the cytoplasm of a specific cell type allows one to distinguish this specific cell type from other cell types with considerable accuracy. (2) That there is a relationship between the concentration of the various elements and the ultrastructural features of the cytoplasmic regions being analyzed. For example, areas rich in ribosomes are also rich in P, K and Mg. (3) These data support the idea that K is directly involved in the control of protein synthesis. The catalog of element concentrations in the cytoplasm of 13 cell types from both mice and rats should be of value to others who seek to answer various questions about these cell types.

Animals↗
PubMed1992

Association of cytoplasmic free Ca2+ gradients with subcellular organelles.

Previous investigations have identified gradients of intracellular free (Ca2+)i (Ca2+i) in the cytoplasm of human fibroblasts. In this study we have compared the spatial distribution of these gradients with the subcellular distribution of cytoplasmic organelles. Using the Ca(2+)-sensitive dye fura-2 and organelle-specific fluorescent dyes, we have found that the highest Ca2+ concentrations are found in the perinuclear cytoplasm and that these regions co-localize with the Golgi apparatus. The area occupied by the endoplasmic reticulum, which includes the Golgi region plus an adjacent area, is also significantly elevated above the average cellular (Ca2+)i. Most mitochondria are located in regions different from those with the highest (Ca2+)i. A variety of phenomena which could have given rise to artifactual (Ca2+)i gradients have been ruled out, including compartmentalization of fura-2 in subcellular organelles, incomplete hydrolysis of fura-2AM esters, and the presence of pH gradients which might change the Ca2+ binding characteristics of fura-2. The existence of gradients in (Ca2+)i between ER and Golgi containing regions of the cytoplasm supports the hypothesis (Sambrook: Cell 61:197-199, 1990) that the traffic of membrane bound vesicles from ER to Golgi is directed by local variations in (Ca2+)i.

Calcium↗
PubMed1986

Organisation of Xenopus egg cytoplasm: response to simulated microgravity.

The cytoplasm of Xenopus fertilised eggs appears to be organised into three major compartments based primarily on the uneven distribution of yolk platelets. There is a shift of these yolk compartments during the first cell cycle that is thought to be involved in the dorsal/ventral morphogenesis of the embryo. The involvement of gravity in Xenopus cytoplasmic organisation and in compartment shifts was addressed by examining, cytologically, the yolk compartments in embryos that developed under the simulated microgravity conditions of the horizontal clinostat. The cytoplasmic organisation into yolk compartments was found to be maintained, and the asymmetric movements of compartments still occurred in eggs that developed on the clinostat. It is suggested that the organisation of Xenopus egg cytoplasm into discrete compartments relies on forces other than those involving gravity (i.e., not density differences), and that the compartment shifts that take place during the first cell cycle are active movements. The variation in compartment size and composition observed from batch to batch of eggs, and to a lesser extent from egg to egg, during this study was addressed.

Animals↗
PubMed2006

Evaluation of the nuclear delivery and intra-nuclear transcription of plasmid DNA condensed with micro (mu) and NLS-micro by cytoplasmic and nuclear microinjection: a comparative study with poly-L-lysine.

BACKGROUND: The efficient nuclear delivery of plasmid DNA (pDNA) is essential for the development of a promising non-viral gene vector. In an attempt to achieve nuclear delivery, NLS-mu, a novel pDNA condenser, was prepared. This consists of mu, a highly potent polypeptide for condensing the pDNA, and a SV40 T antigen-derived nuclear localization signal (NLS(SV40)). METHODS: The utility of NLS-mu was assessed in terms of green fluorescent protein (GFP) expression after cytoplasmic and nuclear microinjection of GFP-encoding pDNA along with the transfection, and compared with mu and poly-L-lysine (PLL). Trans-gene expression after cytoplasmic microinjection was affected by the efficiencies of nuclear transfer and following intra-nuclear transcription. To evaluate the nuclear transfer process separately, we introduced a parameter, a nuclear transfer score (NT score), which was calculated as the trans-gene expression after cytoplasmic microinjection divided by that after nuclear microinjection. RESULTS: As expected, the rank order of trans-gene expression after the transfection and cytoplasmic microinjection was NLS-mu > mu > PLL. However, the calculated NT scores were unexpectedly ranked as mu = NLS-mu > PLL, suggesting that mu, and not NLS(SV40), is responsible for the nuclear delivery of pDNA. In addition, confocal images of rhodamine-labeled pDNA indicated that pDNA condensed with mu and NLS-mu was delivered as a condensed form. In comparing the nuclear transcription, the rank order of trans-gene expression after nuclear microinjection was PLL = NLS-mu > mu, suggesting that intra-nuclear transcription is inhibited by efficient condensation by mu, and is avoided by the attachment of NLS(SV40). CONCLUSIONS: Collectively, NLS-mu, which consists of chimeric functions, is an excellent DNA condenser, and the process is based on mu-derived nuclear transfer and NLS(SV40)-derived efficient intra-nuclear transcription.

Cell Nucleus↗
PubMed1991

Activation of human neutrophils by phorbol ester decreases the cytoplasm compactness and the lactoferrin content of the granulocytes.

Human neutrophils isolated from the blood were incubated in vitro for 30 min with 25 ng/ml of phorbol 12-myristate 13-acetate (PMA), a protein kinase C activator, to study its effect on the fine structure of granulocytes and on the subcellular distribution of lactoferrin (Lf). Flow cytometry analysis of the human neutrophils showed that PMA induced a decrease in size and granularity of the cells. By electron microscopy, the PMA-treated cells showed numerous empty vesicles, smoothing of the cell surface, and a marked decrease in the compactness of the cytoplasmic ground substance. High-resolution immunogold ultracytochemistry showed that neutrophils lost most of their content in Lf after the PMA incubation. In thin sections, the cytoplasmic compartment of PMA-treated neutrophils contained an average of 1.03 +/- 0.3 Lf-positive vesicles per microns 2, whereas control granulocytes showed an average of 5.72 +/- 1.49 Lf vesicles per microns 2 of cytoplasm. Most of PMA-treated neutrophils kept some Lf-positive vesicles; a significant minority (10-15%) of the granulocytes showed cytological features of cell death. We conclude that the PMA-induced neutrophil activation is associated with microanatomical changes that include i) exocytosis of most, but not all, of the Lf-bearing vesicles; ii) rounding up of the cell outline; and iii) decrease in the compactness of the cytoplasmic ground substance.

Cytoplasm↗
PubMed1994

Fate and composition of cytoplasmic droplet of hamster epididymal spermatozoa.

Observations on sperm maturation in the hamster (Mesocricetus auratus) epididymis revealed that the cytoplasmic droplet migrates from the proximal position of the sperm flagellum to the end of the midpiece. This process begins in the testis or vas efferens and ends in the cauda region of the epididymis. A study of different regions of the epididymis and vas deferens demonstrated that the cytoplasmic droplet is not released from the sperm into the luminal fluid. An ultrastructural study of the cytoplasmic droplet demonstrated changes in its morphology as its position moved distally along the midpiece. Membranous components called saccules or vesicles, believed to be remnants of the Golgi apparatus present in the cytoplasmic droplet, changed their morphology during the migration process. Inclusion bodies within vesicles were released to the lumen at the levels of the cauda epididymis and the vas deferens.

Animals↗
PubMed1993

Protein synthesis-dependent cytoplasmic translocation of p53 protein after serum stimulation of growth-arrested MCF-7 cells.

p53 protein was localized in the cytoplasm of growing and in the nucleus of growth-arrested MCF-7 cells. While the absolute amount and rate of synthesis of p53 in growing and arrested cells were nearly the same, the protein in growing cells was phosphorylated to a greater extent than in arrested cells. The abilities of the cytoplasmic and nuclear p53 proteins to bind to DNA sequences specific for p53 protein binding did not differ remarkably despite their differential phosphorylation levels. Serum-induced translocation of the p53 protein from the nucleus to the cytoplasm, as well as DNA and protein synthesis, were inhibited by cycloheximide. These results suggest that the DNA synthesis-associated cytoplasmic translocation of p53 protein in response to serum stimulation depends on de novo protein synthesis and not on alteration of the protein's ability to bind to specific DNA sequences.

Base Sequence↗
PubMed1995

Messenger RNA encoding an estrogen-dependent oviduct secretory protein in the sheep is localized in the apical tips and basal compartments of fimbria and ampulla epithelial cells implying translation at unique cytoplasmic foci.

Data from our laboratory have shown that an estrogen (E2)-dependent M(r) 90,000-92,000 protein and its mRNA are synthesized and expressed in abundant amounts at estrus from the fimbria and ampulla, not isthmus, oviduct of the sheep. Immunocytochemical studies have shown that the M(r) 90,000-92,000 protein is contained in apical secretory granules of oviduct epithelial cells. The objective of this study was to determine whether the mRNA for the E2-dependent oviduct protein was localized and compartmentalized in similar manner. Fimbria, ampulla, and isthmus oviducts obtained from estrous ewes were flash frozen in liquid nitrogen, cryosectioned, fixed in 4% paraformaldehyde, hybridized with digoxigenin (DIG)-labeled oviduct-specific riboprobes, incubated in anti-DIG antibodies conjugated with alkaline phosphatase, and developed in color substrate. Oviduct protein-specific transcripts were localized to basal perinuclear compartments and, surprisingly, at sites distant from the nucleus in the apical cytoplasm of epithelial cells in the fimbria and ampulla. No specific reaction product was observed in the underlying mucosa or smooth muscle layers. Oviduct protein mRNA was contained predominantly in the apical cytoplasm of epithelial cells at the free margins of mucosal folds and in the basal regions of cells located at the crypts of longitudinal folds. No reaction product was present when sections of the fimbria and ampulla oviduct of estrous ewes were incubated in sense riboprobe to the oviduct protein. In addition, when sections of the isthmus oviduct obtained from estrous ewes or fimbira and ampulla oviducts from long-term ovariectomized ewes were hybridized with antisense riboprobes no specific reaction product was detected. Electron microscopy of oviduct protein mRNA containing areas revealed the presence of secretory granules, rough endoplasmic reticulum (RER) and Golgi in the apical cytoplasm, and RER in the basal regions of epithelial cells. These data show that the mRNA encoding an E2-dependent oviduct-specific protein is distributed in epithelial cells at perinuclear foci and at sites distant from the nucleus, which are also the sites of protein localization and protein synthesizing organelles, implying translation at unique cytoplasmic foci.

Animals↗
PubMed1997

Design, synthesis, expression, and characterization of the genes for mouse Fc gamma RIIb1 and Fc gamma RIIb2 cytoplasmic regions.

The cytoplasmic regions of the mouse low-affinity Fc gamma RII isoforms, mFc gamma RIIb1, and mFc gamma RIIb2, play a key role in signal transduction by mediating different cellular functions. mFc gamma RIIb1 has a 94-residue cytoplasmic region, whereas mFc gamma RIIb2 has a 47-residue cytoplasmic region. Genes encoding the cytoplasmic regions of mFc gamma RIIb1 (b1-94) and mFc gamma RIIb2 (b2-47) were designed, synthesized, and expressed as fusion proteins in Escherichia coli. A sequence-specific protease, thrombin, was used to release the b1-94 peptide, which was purified by using HPLC. The b2-47 peptide was synthesized chemically. CD spectropolarimetry was employed to examine the secondary structures of b1-94 and b2-47. These studies were conducted in aqueous solution, in mixtures of water and trifluoroethanol or methanol, and as a function of temperature. The results indicate that the b1-94 and b2-47 structures are sensitive functions of the solvent environment, and that nonaqueous solvents induce significant alpha-helical structure.

Amino Acid Sequence↗
PubMed1997

Cell type and spatial location dependence of cytoplasmic viscosity measured by time-resolved fluorescence microscopy.

Information on the cell type and spatial location dependence of cytoplasmic viscosity would be very useful in understanding some of the processes occurring in the cell. For this purpose, fluorescent dye kiton red (sulforhodamine B) was loaded into a variety of cells such as Swiss 3T3 fibroblasts, human mononuclear cells, Sarcoma-180 tumor cells, Chinese hamster ovary cells, plant cells from Digitalis lanata, stamen hair cells of Tradescantia, and guard mother cells of Allium cepa. Space-resolved measurements of cytoplasmic viscosity were carried out by using an experimental set-up wherein a picosecond laser system was coupled with an epifluorescence microscope. The spatial resolution of this set-up was approximately 1.0 micron, and reliable dynamic fluorescence measurements could be obtained from 10(2) to 10(3) fluorescent molecules. Fluorescence lifetime measurements showed that a large fraction (approximately 70%) of kiton red was in the free form. Fluorescence anisotropy decay of kiton red in cells was analyzed by a two population (free and bound) model. The microviscosity of cytoplasm was estimated from the anisotropy decay kinetics of the free probe. It was found that the cytoplasmic viscosity is dependent on both the cell type and spatial location within a cell. Furthermore, both the average value of viscosity and spatial variation within a cell were larger in the plant cells when compared to the animal cells. Model studies in various simpler systems have shown that the higher viscosity observed in some part of the cell could be due to either physical restriction and/or the presence of high concentrations of small solutes and macromolecules.

3T3 Cells↗
PubMed1999

Loss of cytoplasmic retention ability of mutant LKB1 found in Peutz-Jeghers syndrome patients.

LKB1 Serine/Threonine (ST) kinase (also called STK11) originally identified in our novel protein kinase search project has recently been recognized as a susceptibility gene of Peutz-Jeghers Syndrome (PJS; MIM 175200). PJS is a dominantly inherited human disorder which is characterized by gastrointestinal hamartomatous polyposis and mucocutaneous melanin pigmentation. Since PJS patients also show a predisposition to a wide spectrum of cancers, it is speculated that LKB1 has a tumor suppressor function. In the present study we have characterized the basic biochemical property of LKB1. In the analysis of mutant LKB1 identified in PJS patients, it was found that one of the mutants, SL26, does not lose its kinase function, but alters its subcellular distribution to accumulate in the nucleus only, whereas wild type LKB1 shows both nuclear and cytoplasmic localization. Domain mapping of the nuclear targeting signal of LKB1 assigned it to its amino terminal side. Furthermore, it was shown that LKB1 also has a cytoplasmic retention ability which is considered defective and pathogenic in the SL26 mutant. It is speculated that subcellular distribution of LKB1 is regulated in the balance of these two forces, importation into the nucleus and retention within the cytoplasm; and the cytoplasmic retention ability is necessary for LKB1 to fulfil its normal function.

AMP-Activated Protein Kinase Kinases↗
PubMed2001

Cytoplasmic gamma actin as a Z-disc protein.

To investigate the precise localization of cytoplasmic gamma actin in skeletal muscle and the relationship to dystrophin molecules, we designed an antibody against the N-terminal peptide of cytoplasmic gamma actin. Western blot analysis using SDS-PAGE and isoelectric focusing (IEF) gel revealed that the antibody reacted only with the actin isoforms having gamma motility, confirming that the antibody is specific to the cytoplasmic (nonmuscle) gamma actin. Immunohistochemical analysis of the skeletal muscle of the adult mouse revealed a dot-like staining pattern of the antibody in transverse sections and a striated staining pattern in longitudinal sections. The double immunostaining technique revealed the colocalization of cytoplasmic gamma actin with alpha-actinin, implying the localization of the actin on the Z-disc. Contrary to previous findings (1), we did not detect the colocalization of cytochrome oxidase, a mitochondria marker, with this actin.

Actins↗
PubMed1996

Binding of CD44 to hyaluronic acid can be induced by multiple signals and requires the CD44 cytoplasmic domain.

Human Jurkat T cells transfected with a human CD44H gene do not bind fluorescein-conjugated hyaluronic acid (F-HA). Activation of Jurkat CD44 transfectant is required for binding to F-HA. Binding can be induced by anti-CD3 monoclonal antibody (Mab), PMA, calcium ionophore, forskolin, or a monoclonal anti-CD44 Mab (F10-44-2). Cytochalasin D, an inhibitor of actin polymerization, inhibited both PMA-induced and anti-CD44 Mab-induced binding. In contrast, only PMA-induced binding was blocked by inhibitors of microtubule functions: colchicine or Taxol. Therefore, binding induced by PMA and anti-CD44 Mab involves different cytoskeletal proteins. The conclusion that interactions between CD44 and cytoskeletal proteins are important for binding was further supported by our observations that the cytoplasmic domain of CD44 is required for both PMA- and anti-CD44 Mab-induced binding. Jurkat CD44 mutant transfectant lacking the last 23 amino acids of the cytoplasmic domain can be induced to bind FHA. In contrast, Jurkat mutant CD44 transfectant lacking the last 57 amino acids of the cytoplasmic domain was unable to bind. Collectively, these data provide supportive evidence that binding activity of CD44 is under the regulation of multiple signal pathways and requires the presence of the cytoplasmic domain.

Amino Acid Sequence↗
PubMed1994

Lack of IgA antineutrophil cytoplasmic antibodies in Henoch-Schönlein purpura and IgA nephropathy.

To verify whether IgA antineutrophil cytoplasmic antibody (ANCA) represents a serologic marker in Henoch-Schönlein purpura (HPS), we examined sera from 41 patients with the disease. Control sera from 28 patients with primary IgA nephropathy (IgA-N), 26 IgG-ANCA-positive vasculitis, and 28 normal controls were also studied. An increased IgA binding to neutrophil cytoplasmic extracts but not to purified ANCA antigens was found in 12.2-14.6% of HSP patients and in 14.3-21.4% of IgA-N patients versus 3.5% of normal controls. IgA binding to neutrophil cytoplasmic extracts correlated with serum IgA levels, IgA-rheumatoid factor, and IgA-fibronectin binding capacity. Moreover, low amounts of IgG and fibronectin were detected as contaminants in neutrophil cytoplasmic extracts and fibronectin could partly inhibit the binding of IgA to "crude" extracts. We conclude that IgA-ANCA are neither diagnostically nor immunologically specific in HSP and IgA-N. Several factors present in the sera of patients with IgA-related nephropathies seem to contribute to the "false-positive" IgA-ANCA demonstrable in these patients.

Adolescent↗
PubMed1996

Anti-monocyte cytoplasmic antibodies in granulomatous disease.

Antibodies reactive with cytoplasmic components of neutrophils (ANCA) have received much attention because of their association with vasculitis and other inflammatory disorders. In this study, ELISA and immunofluorescence assays were employed to detect antimonocyte-specific antibodies and similar assays were used in parallel to detect anti-neutrophil cytoplasmic antibodies in a range of patient sera: Wegener's granulomatosis (14), Crohn's disease (46), ulcerative colitis (43), sarcoidosis (40), rheumatoid factor positive (15), and normal controls (22). Using an ELISA, anti-monocyte antibodies were detected in (figures in parentheses represent anti-neutrophil results): Wegener's granulomatosis, 79% (93%); sarcoidosis, 30% (5%); Crohn's disease, 20% (11%); ulcerative colitis, 0% (49%); rheumatoid factor-positive sera, 0% (0%). Excellent concordance (>98%) was found between the ELISA and immunofluorescence assays and all of the anti-monocyte antibodies gave a cytoplasmic pattern of staining. This is the first report demonstrating the presence of antibodies specific to the cytoplasmic components of monocytes in patients with granulomatous disease and these findings enhance our understanding of auto-antibody responses against phagocytic cell components.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1997

Cytoplasmic localization of cyclin D3 in seminiferous tubules during testicular development.

Using a newly developed polyclonal antibody against murine cyclin D3, we have found that protein levels of cyclin D3 were highly detectable only in thymus and testis in rats. Since testis offer unique opportunities to examine the cell cycle in vivo, we examined the temporal and spatial expression of cyclin D3 and the DNA synthesis indicator, proliferating cell nuclear antigen (PCNA), in the rat testis during development. The protein levels of cyclin D3 protein in testis from 7 days to 3 months old were almost constant and then decreased gradually thereafter. The protein levels of cyclin D1 and PCNA were high in the testis of 7- and 14-day-old rats and decreased during testicular development. In the seminiferous tubules of 7-day-old newborns, cyclin D3 was surprisingly located in cytoplasm of stem cells that had bigger nuclei than the nuclei of surrounding cells. Interestingly, cyclin D3 immunopositive cells did not immunostain with PCNA in nuclei. In the adult testis, anti-cyclin D3 antibody strongly stained the cytoplasm of early stage primary spermatocytes, lightly stained pachytene spermatocytes, but did not stain elongated spermatids. There was no detectable cyclin D3 in Sertoli cells, interstitial cells, or fibroblasts within seminiferous tubules, or in blood vessels within the interstitial matrix. The known cyclin D3 partner, cyclin dependent kinase 4, was located mainly in nuclei of spermatogonia and in early stage primary spermatocytes. Strong PCNA immunopositive staining was located in the nuclei of spermatogonia in adult testis. These results indicate that cyclin D3 is detectable in meiotically active male germ cells (PCNA-negative cells), but is conspicuously absent from mitotically active spermatogonia (PCNA-positive cells). Moreover, in contrast to in vitro reports, cyclin D3 is not located in the nucleus, but rather in the cytoplasm of male germ cells in vivo. Taken together, the presence of cyclin D3 in spermatocytes and its location in the cytoplasm lead us to speculate that cyclin D3 may have functions in male germ cells other than mitosis.

Aging↗
PubMed1999

The cytochrome b5 tail anchors and stabilizes subdomains of human DNA topoisomerase II alpha in the cytoplasm of retrovirally infected mammalian cells.

DNA topoisomerase II (topo II) is the target of many anticancer drugs and is often altered in drug-resistant cell lines. In some tumor cell lines truncated isoforms of topo IIalpha are localized to the cytoplasm. To study the localization and function of individual enzyme domains, we have epitope-tagged several fragments of human topo IIalpha and expressed them by retroviral infection of rodent and human cells. We find that fusion of the topo II fragments to the hydrophobic tail of human liver cytochrome b5 anchors the fusion protein to the outer face of cytoplasmic membranes, as determined by colocalization with calnexin and selective detergent permeabilization. Moreover, whereas the minimal ATPase domain (aa 1-266) is weakly and diffusely expressed, addition of the cytb5 anchor (1-266-b5) increases its steady-state level 16-fold with no apparent toxicity. Similar results are obtained with the complete ATPase domain (aa 1-426). A C-terminal domain (aa 1030-1504) of human topo IIalpha containing an intact dimerization motif is stably expressed and accumulates in the nucleus. Fusion to the cytb5 anchor counteracts the nuclear localization signal and relocalizes the protein to cytoplasmic membranes. In conclusion, we describe a technique that stabilizes and targets retrovirally expressed proteins such that they are exposed on the cytoplasmic surface of cellular membranes. This approach may be of general use for regulating the nuclear accumulation of drugs or proteins in living cells.

Animals↗