Mechanism of toxic action of fluoride in dental fluorosis: whether trimeric G proteins participate in the disturbance of intracellular transport of secretory ameloblast exposed to fluoride

1998 ◽  
Vol 72 (12) ◽  
pp. 798-806 ◽  
Author(s):  
Saburou Matsuo ◽  
Ken-ichi Kiyomiya ◽  
Masaru Kurebe
Keyword(s):  
G Proteins ◽  
Intracellular Transport ◽  
Dental Fluorosis ◽  
Toxic Action ◽  
Secretory Ameloblast

Generation of an erythrocyte vesicle transport system by Plasmodium falciparum malaria parasites

Blood ◽  
2003 ◽  
Vol 102 (9) ◽  
pp. 3420-3426 ◽  
Author(s):  
Theodore F. Taraschi ◽  
Megan O'Donnell ◽  
Sandra Martinez ◽  
Timothy Schneider ◽  
Darin Trelka ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasma Membrane ◽  
G Proteins ◽  
Intracellular Transport ◽  
Surface Membrane ◽  
Plasmodium Falciparum Malaria ◽  
Vesicle Transport ◽  
Aluminum Fluoride ◽  
Sensitive Factor ◽  
Erythrocyte Plasma Membrane

AbstractThe asexual maturation of Plasmodium falciparum is accompanied by the transport of parasite-encoded proteins to the erythrocyte plasma membrane. Activation of G proteins by treatment with aluminum fluoride produced an accumulation within the erythrocyte cytosol of vesicles coated with Plasmodium homologues of COPII and N-ethylmaleimide-sensitive factor, proteins involved in intracellular transport between the Golgi apparatus and the endoplasmic reticulum. These vesicles contain malarial proteins that appear on the erythrocyte plasma membrane, as well as actin and myosin. It is proposed that the parasite adapted a process well established for intracellular transport to mediate the extracellular movement of its proteins through the erythrocyte cytosol to the surface membrane.

Rab6 is associated with a compartment that transports rhodopsin from the trans-Golgi to the site of rod outer segment disk formation in frog retinal photoreceptors

1993 ◽  
Vol 106 (3) ◽  
pp. 803-813 ◽  
Author(s):  
D. Deretic ◽  
D.S. Papermaster
Keyword(s):  
G Proteins ◽  
Outer Segment ◽  
Intracellular Transport ◽  
Integral Membrane Protein ◽  
Sucrose Density Gradient ◽  
Disk Formation ◽  
Rod Outer Segment ◽  
Golgi Vesicles ◽  
Retinal Photoreceptors ◽  
Retinal Rod

The biogenesis of light sensitive membranes in retinal rod photoreceptors involves polarized sorting and targeting of newly synthesized rhodopsin to a specialized domain, the rod outer segment (ROS). We have isolated and characterized the population of post-Golgi membranes that mediate intracellular transport of rhodopsin. In the present study we have examined the association of small (20-25 kDa) GTP-binding (G) proteins with these membranes. We found that one of the small G proteins, rab6, behaves like an integral membrane protein of the post-Golgi vesicles, although approximately 30% of rab6 is soluble. The distribution of the membrane-associated and the soluble forms is highly polarized. By confocal and EM immunocytochemistry it can be seen that most of rab6 is associated with the photoreceptor trans-Golgi cisternae, trans-Golgi network (TGN) and post-Golgi vesicles. The photoreceptor axon and synaptic terminal are unlabeled, but dendrites of deeper retinal layers are labeled. The distribution of rab6 across sucrose density gradient fractions parallels the distribution of sialyltransferase (a TGN marker) activity. About 9% of membrane-bound rab6 is associated, however, with the rhodopsin-bearing sialyltransferase-free post-Golgi vesicles, which represent a very small fraction (< 1%) of the total retinal membranes. Rab6 is absent from the mature ROS disk membranes but it is present at the sites of new ROS disk formation and in the ROS cytoplasm. This suggests that rab6 becomes soluble upon disk membrane formation. Therefore, rab6 may function not only as a component of the sorting machinery of photoreceptors that delivers rhodopsin to its appropriate subcellular domain but may also participate in some aspects of ROS disk morphogenesis.

Main Features of Basal Cytoxicity: Sites of Toxic Action and Interaction in the Pollen Tube Cell

1996 ◽  
Vol 24 (3) ◽  
pp. 429-434
Author(s):  
Udo Kristen
Keyword(s):  
Intracellular Transport ◽  
Chemical Compounds ◽  
Cell Types ◽  
Pollen Tubes ◽  
Eukaryotic Cell ◽  
Toxic Action ◽  
Membrane Flow ◽  
Cytotoxic Compounds ◽  
Tube Cell ◽  
Basal Cytotoxicity

Pollen tubes have frequently been used to determine the cytotoxic potentials of various chemical compounds and to study the effects of toxic action in the tube cell. In this paper, the main results of these studies are used to develop a model for understanding basal cytotoxicity. The following eight intracellular sites or functions, which are known to play a significant role as targets for toxic action, are considered: mitochondria, intracellular transport, membrane flow, the endoplasmic reticulum and Golgi apparatus, lipid and protein synthesis, carbohydrate synthesis, the cytoskeleton, and the plasma membrane. The reactions of these targets to certain representative cytotoxic compounds frequently applied to pollen tubes are reviewed. These reactions, most of which were observed by using electron microscopy and immunofluorescence microscopy, are discussed in relation to cell growth inhibition. In addition, interactions between the target sites are described and schematically presented. The set of targets mentioned above is representative of what is found in the majority of eukaryotic cell types. Therefore, it is not surprising that many of the cell types which are used in cytotoxicology produce values within the same logarithmic range.

scholarly journals Fusogenicity of the Ghana Virus (Henipavirus: Ghanaian bat henipavirus) Fusion Protein is Controlled by the Cytoplasmic Domain of the Attachment Glycoprotein

Viruses ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 800
Author(s):  
Kathleen Voigt ◽  
Markus Hoffmann ◽  
Jan Felix Drexler ◽  
Marcel Alexander Müller ◽  
Christian Drosten ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Fusion Protein ◽  
G Proteins ◽  
Intracellular Transport ◽  
Transmembrane Domain ◽  
Cytoplasmic Tail ◽  
Surface Expression ◽  
Hendra Virus ◽  
Structural Domains ◽  
Glycoprotein G

The Ghana virus (GhV) is phylogenetically related to the zoonotic henipaviruses Nipah (NiV) and Hendra virus. Although GhV uses the highly conserved receptor ephrin-B2, the fusogenicity is restricted to cell lines of bat origin. Furthermore, the surface expression of the GhV attachment glycoprotein (G) is reduced compared to NiV and most of this protein is retained in the endoplasmic reticulum (ER). Here, we generated truncated as well as chimeric GhV G proteins and investigated the influence of the structural domains (cytoplasmic tail, transmembrane domain, ectodomain) of this protein on the intracellular transport and the fusogenicity following coexpression with the GhV fusion protein (F). We demonstrate that neither the cytoplasmic tail nor the transmembrane domain is responsible for the intracellular retention of GhV G. Furthermore, the cytoplasmic tail of GhV G modulates the fusogenicity of GhV F and therefore controls the species-restricted fusogenicity of the GhV surface glycoproteins.

Changes Occur in Plasma Membrane Turnover when K562 Leukemia Cells are Induced to Differentiate

1982 ◽  
Vol 40 ◽  
pp. 286-287
Author(s):  
L. M. Marshall
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Intracellular Transport ◽  
Parent Cell ◽  
Membrane Turnover ◽  
Coated Pits ◽  
Surface Distribution ◽  
Specific Proteins ◽  
Erythroleukemic Cell ◽  
Specific Membrane

A human erythroleukemic cell line, metabolically blocked in a late stage of erythropoiesis, becomes capable of differentiation along the normal pathway when grown in the presence of hemin. This process is characterized by hemoglobin synthesis followed by rearrangement of the plasma membrane proteins and culminates in asymmetrical cytokinesis in the absence of nuclear division. A reticulocyte-like cell buds from the nucleus-containing parent cell after erythrocyte specific membrane proteins have been sequestered into its membrane. In this process the parent cell faces two obstacles. First, to organize its erythrocyte specific proteins at one pole of the cell for inclusion in the reticulocyte; second, to reduce or abolish membrane protein turnover since hemoglobin is virtually the only protein being synthesized at this stage. A means of achieving redistribution and cessation of turnover could involve movement of membrane proteins by a directional lipid flow. Generation of a lipid flow towards one pole and accumulation of erythrocyte-specific membrane proteins could be achieved by clathrin coated pits which are implicated in membrane endocytosis, intracellular transport and turnover. In non-differentiating cells, membrane proteins are turned over and are random in surface distribution. If, however, the erythrocyte specific proteins in differentiating cells were excluded from endocytosing coated pits, not only would their turnover cease, but they would also tend to drift towards and collect at the site of endocytosis. This hypothesis requires that different protein species are endocytosed by the coated vesicles in non-differentiating than by differentiating cells.

Confocal microscopy of the cytoskeleton in living plant cells following microinjection of fluorescent probes

1993 ◽  
Vol 51 ◽  
pp. 130-131
Author(s):  
Ann Cleary
Keyword(s):  
Cell Division ◽  
Fluorescent Probes ◽  
Actin Filaments ◽  
Intracellular Transport ◽  
Cell Structure ◽  
Plant Cells ◽  
Cell Plate ◽  
Cell Cortex ◽  
Living Plant ◽  
Rhodamine Phalloidin

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.

Toxic action/toxicity

2000 ◽  
Vol 75 (1) ◽  
pp. 95-127 ◽  
Author(s):  
D. E. HATHWAY
Keyword(s):  
Toxic Action
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