The ultrastructure of the cell surface and plasma membrane of exponential and stationary phase cells of Schizosaccharomyces pombe, grown in different media

1984 ◽  
Vol 137 (2) ◽  
pp. 128-134 ◽  
Author(s):  
P. Walther ◽  
M. M�ller ◽  
M. E. Schweingruber
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Stationary Phase ◽  
Schizosaccharomyces Pombe

scholarly journals Dissection of the relative contribution of the Schizosaccharomyces pombe Ctr4 and Ctr5 proteins to the copper transport and cell surface delivery functions

Microbiology ◽  
2011 ◽  
Vol 157 (4) ◽  
pp. 1021-1031 ◽  
Author(s):  
Jude Beaudoin ◽  
Dennis J. Thiele ◽  
Simon Labbé ◽  
Sergi Puig
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Schizosaccharomyces Pombe ◽  
Transmembrane Domain ◽  
Chimeric Proteins ◽  
High Affinity ◽  
Relative Contribution ◽  
Eukaryotic Organisms ◽  
Transport Complex ◽  
Cu Uptake

The Ctr1 family of proteins mediates high-affinity copper (Cu) acquisition in eukaryotic organisms. In the fission yeast Schizosaccharomyces pombe, Cu uptake is carried out by a heteromeric complex formed by the Ctr4 and Ctr5 proteins. Unlike human and Saccharomyces cerevisiae Ctr1 proteins, Ctr4 and Ctr5 are unable to function independently in Cu acquisition. Instead, both proteins physically interact with each other to form a Ctr4–Ctr5 heteromeric complex, and are interdependent for secretion to the plasma membrane and Cu transport activity. In this study, we used S. cerevisiae mutants that are defective in high-affinity Cu uptake to dissect the relative contribution of Ctr4 and Ctr5 to the Cu transport function. Functional complementation and localization assays show that the conserved Met-X3-Met motif in transmembrane domain 2 of the Ctr5 protein is dispensable for the functionality of the Ctr4–Ctr5 complex, whereas the Met-X3-Met motif in the Ctr4 protein is essential for function and for localization of the hetero-complex to the plasma membrane. Moreover, Ctr4/Ctr5 chimeric proteins reveal unique properties found either in Ctr4 or in Ctr5, and are sufficient for Cu uptake on the cell surface of Sch. pombe cells. Functional chimeras contain the Ctr4 central and Ctr5 carboxyl-terminal domains (CTDs). We propose that the Ctr4 central domain mediates Cu transport in this hetero-complex, whereas the Ctr5 CTD functions in the regulation of trafficking of the Cu transport complex to the cell surface.

Topographical stability of lateral regions of the Schizosaccharomyces pombe plasma membrane as revealed by invagination characteristics

1988 ◽  
Vol 34 (9) ◽  
pp. 1063-1068 ◽  
Author(s):  
Kanji Takeo ◽  
Kazuko Nishimura ◽  
Makoto Miyaji
Keyword(s):  
Plasma Membrane ◽  
Stationary Phase ◽  
Schizosaccharomyces Pombe ◽  
Freeze Fracture ◽  
Exponential Phase ◽  
High Density ◽  
The Stability

The characteristics, especially the stability, of plasma-membrane invaginations in Schizosaccharomyces pombe were studied using freeze-fracture techniques. The plasma membrane of exponential-phase S. pombe was characterized by the uninvaginated growing pole(s) and by the existence of particularly long invaginations, reaching up to 5 μm, in the nongrowing lateral regions. The stationary-phase plasma membrane was characterized by densely invaginated cell poles and by the high density of invaginations. After reinoculation of stationary-phase cells in fresh media, preexisting invaginations in the cell poles disappeared when the latter became the growing pole. In lateral regions of the plasma membrane, however, deep invaginations, characteristic of the stationary phase, were well conserved. The results obtained suggest the topographical stability of nongrowing lateral regions of the S. pombe plasma membrane.

Glycoconjugates on the surface of spores of the pathogenic fungus Phytophthora cinnamomi studied using fluorescence and electron microscopy and flow cytometry

1990 ◽  
Vol 36 (3) ◽  
pp. 183-192 ◽  
Author(s):  
A. R. Hardham ◽  
E. Suzaki
Keyword(s):  
Flow Cytometry ◽  
Plasma Membrane ◽  
Cell Surface ◽  
Phytophthora Cinnamomi ◽  
Pathogenic Fungus ◽  
Fluorescein Isothiocyanate ◽  
Pathogenic Fungi ◽  
Surface Flow ◽  
Soybean Agglutinin ◽  
Binding Material

Glycoconjugates on the surface of zoospores and cysts of the pathogenic fungus Phytophthora cinnamomi have been studied using fluorescein isothiocyanate labelled lectins for fluorescence microscopy and flow cytometry, and ferritin- and gold-labelled lectins for ultrastructural analysis. Of the five lectins used, only concanavalin A (ConA) binds to the surface of the zoospores, including the flagella and water expulsion vacuole. This suggests that of accessible saccharides, glucosyl or mannosyl residues predominate on the outer surface of the zoospore plasma membrane. Early in encystment, a system of flat disc-like cisternae, which underlie the zoospore plasma membrane, vesiculate. These and other small peripheral vesicles quickly disappear. After the induction of encystment, ConA is no longer localised close to the plasma membrane but binds to material loosely associated with the cell surface. Quantitative measurements by flow cytometry indicate that the ConA-binding material is gradually lost from the cell surface. The cyst wall is weakly labelled, but the site of germ tube emergence stains intensely. During the first 2 min after the induction of encystment, material that binds soybean agglutinin, Helix pommatia agglutinin, and peanut agglutinin appears on the surface of the fungal cells. The distribution of this material, rich in galactosyl or N-acetyl-D-galactosaminosyl residues, is initially patchy, but by 5 min the material evenly coats most of the cell surface. Labelling of zoospores in which intracellular sites are accessible indicates that the soybean agglutinin binding material is stored in vesicles that lie beneath the plasma membrane. Quantitation of soybean agglutinin labelling shows that maximum binding occurs 2–3 min after the induction of encystment. Key words: cell surface, flow cytometry, lectins, pathogenic fungi, Phytophthora cinnamomi.

scholarly journals CELL SURFACE IMMUNOGLOBULIN

1972 ◽  
Vol 135 (6) ◽  
pp. 1392-1405 ◽  
Author(s):  
Charles J. Sherr ◽  
Sonia Baur ◽  
Inge Grundke ◽  
Joseph Zeligs ◽  
Barbara Zeligs ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Plasma Membrane ◽  
Cell Surface ◽  
Noncovalent Interactions ◽  
Subcellular Fractionation ◽  
Splenic Lymphocytes ◽  
Surface Immunoglobulin ◽  
Established Line ◽  
Intracellular Proteins ◽  
Daudi Cells

Cells from an established line of Burkitt lymphoma (Daudi) were enzymatically radioiodinated, and labeled Ig from the cell surface was isolated and studied. Subcellular fractionation of labeled cells confirmed that intracellular proteins from the cytoplasm are not iodinated by this method. Radioactive Ig was identified as monomeric (8S) IgM, and an average of 105 Ig molecules was found per cell. Ig molecules could be released from the plasma membrane by detergent lysis under nonreducing conditions indicating that attachment of Ig to the plasma membrane occurs via noncovalent interactions. The ratio of µ/L radioactivity in surface Ig was the same as that of total cellular Ig radioiodinated in solution suggesting that a large portion of the Fc fragment is not buried within the membrane. In contrast to the results obtained with cell surface Ig, most intracellular Ig was found as "free" µ- and L chains regardless of whether lysates were labeled with 125I or cells were labeled with leucine-3H. The results indicate that only a small percentage of the total Ig of Daudi cells is associated with the cell surface and suggest that covalent assembly of Ig occurs at or near the time that the molecule becomes part of the plasma membrane. Similarities between cell surface Ig on normal splenic lymphocytes and Daudi cells suggest that the latter is a neoplasm of bone marrow-derived lymphocytes.

scholarly journals Vesicular Transport Is Not Required for the Cytoplasmic Pool of Cholera Toxin To Interact with the Stimulatory Alpha Subunit of the Heterotrimeric G Protein

2004 ◽  
Vol 72 (12) ◽  
pp. 6826-6835 ◽  
Author(s):  
Ken Teter ◽  
Michael G. Jobling ◽  
Randall K. Holmes
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Cholera Toxin ◽  
G Protein ◽  
Vesicular Transport ◽  
Cytotoxic Action ◽  
Anterograde Transport ◽  
Heterotrimeric G Protein ◽  
Α Subunit ◽  
Vesicular Traffic

ABSTRACT Cholera toxin (CT) moves from the cell surface to the endoplasmic reticulum (ER) by retrograde vesicular transport. The catalytic A1 polypeptide of CT (CTA1) then crosses the ER membrane, enters the cytosol, ADP-ribosylates the stimulatory α subunit of the heterotrimeric G protein (Gsα) at the cytoplasmic face of the plasma membrane, and activates adenylate cyclase. The cytosolic pool of CTA1 may reach the plasma membrane and its Gsα target by traveling on anterograde-directed transport vesicles. We examined this possibility with the use of a plasmid-based transfection system that directed newly synthesized CTA1 to either the ER lumen or the cytosol of CHO cells. Such a system allowed us to bypass the CT retrograde trafficking itinerary from the cell surface to the ER. Previous work has shown that the ER-localized pool of CTA1 is rapidly exported from the ER to the cytosol. Expression of CTA1 in either the ER or the cytosol led to the activation of Gsα, and Gsα activation was not inhibited in transfected cells exposed to drugs that inhibit vesicular traffic. Thus, anterograde transport from the ER to the plasma membrane is not required for the cytotoxic action of CTA1.

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