Mosaic structure in the plasma membrane: spiral arrays of subunits in the cytoplasmic tubules of lamprey chloride cells

1982 ◽  
Vol 56 (1) ◽  
pp. 441-452
Author(s):  
T. Hatae ◽  
E.L. Benedetti
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
High Salinity ◽  
Petromyzon Marinus ◽  
Freeze Fracture ◽  
Chloride Cell ◽  
Chloride Cells ◽  
Ionic Homeostasis ◽  
Electron Dense Material ◽  
Basolateral Plasma Membrane

The membrane architecture of the cytoplasmic tubules in lamprey chloride cells has been studied by electron microscopy using thin-section and freeze-fracture techniques. The chloride cell of lampreys (Lampetra japonica, Petromyzon marinus) is largely occupied with a continuous network of cytoplasmic tubules, which are derived from the invagination of the basolateral plasma membrane. The lumenal surface of this tubular network is covered with spirally wound parallel rows of electron-dense material, which consist of linear aggregates of particles. Freeze-fracture of the membrane of the tubules also shows spiral arrangements of particles (approximately 9 nm in diameter) on the P-face and complementary shallow grooves on the E-face. These arrangements of particles are about 17 nm apart and wound at a pitch of about 45 degrees. These complex organizations of the membrane of the tubules are probably the sites of transport of ion and water, which is essential for the maintenance of ionic homeostasis in both low- and high-salinity environments.

Freeze fracture of the gill epithelium of euryhaline teleost fish

1980 ◽  
Vol 238 (3) ◽  
pp. R207-R212 ◽  
Author(s):  
C. Sardet
Keyword(s):  
Plasma Membrane ◽  
Tight Junctions ◽  
Teleost Fish ◽  
Freeze Fracture ◽  
Chloride Cells ◽  
Gill Epithelium ◽  
Functional Importance ◽  
Seawater Adaptation ◽  
Basolateral Plasma Membrane ◽  
Euryhaline Teleost

We briefly discuss the information one can obtain using freeze fracture. We used this technique to precisely identify the types of junctions that link the cells of the gill epithelium of euryhaline teleosts. In particular we demonstrate that seawater adaptation is characterized by the appearance of new apical tight junctions between chloride cells. Another particularity of these cells, the extensive network of tubules, extension of the basolateral plasma membrane, is shown to be made of repetitive units. We discuss the functional importance of the observations with respect to the adaptation of fish to different salinities.

scholarly journals The surface epithelium of teleostean fish gills. Cellular and junctional adaptations of the chloride cell in relation to salt adaptation.

1979 ◽  
Vol 80 (1) ◽  
pp. 96-117 ◽  
Author(s):  
C Sardet ◽  
M Pisam ◽  
J Maetz
Keyword(s):  
Salt Water ◽  
Freeze Fracture ◽  
Morphological Characteristics ◽  
Chloride Cell ◽  
Chloride Cells ◽  
Surface Epithelium ◽  
Salt Adaptation ◽  
Resistance Pathway ◽  
Shallow Junctions ◽  
Respiratory Cells

Various species of teleostean fishes were adapted to fresh or salt water and their gill surface epithelium was examined using several techniques of electron microscopy. In both fresh and salt water the branchial epithelium is mostly covered by flat respiratory cells. They are characterized by unusual outer membrane fracture faces containing intramembranous particles and pits in various stages of ordered aggregation. Freeze fracture studies showed that the tight junctions between respiratory cells are made of several interconnecting strands, probably representing high resistance junctions. The organization of intramembranous elements and the morphological characteristics of the junctions do not vary in relation to the external salinity. Towards the base of the secondary gill lamellae, the layer of respiratory cells is interrupted by mitochondria-rich cells ("chloride cells"), also linked to respiratory cells by multistranded junctions. There is a fundamental reorganization of the chloride cells associated with salt water adaptation. In salt water young adjacent chloride cells send interdigitations into preexisting chloride cells. The apex of the seawater chloride cell is therefore part of a mosaic of sister cells linked to surrounding respiratory cells by multistranded junctions. The chloride cells are linked to each other by shallow junctions made of only one strand and permeable to lanthanum. It is therefore suggested that salt water adaptation triggers a cellular reorganization of the epithelium in such a way that leaky junctions (a low resistance pathway) appear at the apex of the chloride cells. Chloride cells are characterized by an extensive tubular reticulum which is an extension of the basolateral plasma membrane. It is made of repeating units and is the site of numerous ion pumps. The presence of shallow junctions in sea water-adapted fish makes it possible for the reticulum to contact the external milieu. In contrast in the freshwater-adapted fish the chloride cell's tubular reticulum is separated by deep apical junctions from the external environment. Based on these observations we discuss how solutes could transfer across the epithelium.

scholarly journals Fusion of liposomes with the plasma membrane of epithelial cells: fate of incorporated lipids as followed by freeze fracture and autoradiography of plastic sections.

1988 ◽  
Vol 107 (6) ◽  
pp. 2511-2521 ◽  
Author(s):  
G Knoll ◽  
K N Burger ◽  
R Bron ◽  
G van Meer ◽  
A J Verkleij
Keyword(s):  
Plasma Membrane ◽  
Apical Cell ◽  
Freeze Fracture ◽  
Freeze Substitution ◽  
Morphological Evidence ◽  
Epithelial Cell Line ◽  
Rapid Freezing ◽  
Intramembrane Particle ◽  
Local Point ◽  
Basolateral Plasma Membrane

The fusion of liposomes with the plasma membrane of influenza virus-infected monolayers of an epithelial cell line, Madin-Darby canine kidney cells (van Meer et al., 1985. Biochemistry. 24:3593-3602), has been analyzed by morphological techniques. The distribution of liposomal lipids over the apical and basolateral plasma membrane domains after fusion was assessed by autoradiography of liposomal [3H]dipalmitoylphosphatidylcholine after rapid freezing or chemical fixation and further processing by freeze substitution and low temperature embedding. Before fusion, radioactivity was solely detected on the apical cell surface, indicating the absence of redistribution artifacts and demonstrating the reliability of lipid autoradiography on both a light and electron microscopical level. After induction of fusion by a low pH treatment, the basolateral plasma membrane domain became progressively labeled, indicative of rapid lateral diffusion of [3H]dipalmitoylphosphatidylcholine in the plasma membrane. Analysis of individual fusion events by freeze fracture after rapid freezing confirmed the rapid diffusion of the liposomal lipids into the plasma membrane, as intramembrane particle-free lipid patches were never observed. After the induction of liposome-cell fusion, well-defined intramembrane particles were present on the otherwise smooth liposomal fracture faces and on the fracture faces of the plasma membrane. Morphological evidence thus was obtained in favor of a local point fusion mechanism with an intramembrane particle as a specific structural fusion intermediate.

Aquaporin-2 localization in clathrin-coated pits: inhibition of endocytosis by dominant-negative dynamin

2002 ◽  
Vol 282 (6) ◽  
pp. F998-F1011 ◽  
Author(s):  
Tian-Xiao Sun ◽  
Alfred Van Hoek ◽  
Yan Huang ◽  
Richard Bouley ◽  
Margaret McLaughlin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Direct Evidence ◽  
Collecting Duct ◽  
Freeze Fracture ◽  
Water Channels ◽  
Dominant Negative ◽  
Coated Pits ◽  
Freeze Fracture Electron Microscopy ◽  
Fracture Electron

Before the identification of aquaporin (AQP) proteins, vasopressin-regulated “water channels” were identified by freeze-fracture electron microscopy as aggregates or clusters of intramembraneous particles (IMPs) on hormonally stimulated target cell membranes. In the kidney collecting duct, these IMP clusters were subsequently identified as possible sites of clathrin-coated pit formation on the plasma membrane, and a clathrin-mediated mechanism for internalization of vasopressin-sensitive water channels was suggested. Using an antibody raised against the extracellular C loop of AQP2, we now provide direct evidence that AQP2 is concentrated in clathrin-coated pits on the apical surface of collecting duct principal cells. Furthermore, by using a fracture-label technique applied to LLC-PK1cells expressing an AQP2- c-myc construct, we show that AQP2 is located in IMP aggregates and is concentrated in shallow membrane invaginations on the surface of forskolin-stimulated cells. We also studied the functional role of clathrin-coated pits in AQP2 trafficking by using a GTPase-deficient dynamin mutation (K44A) to inhibit clathrin-mediated endocytosis. Immunofluorescence labeling and freeze-fracture electron microscopy showed that dominant-negative dynamin 1 and dynamin 2 mutants prevent the release of clathrin-coated pits from the plasma membrane and induce an accumulation of AQP2 on the plasma membrane of AQP2-transfected cells. These data provide the first direct evidence that AQP2 is located in clathrin-coated pits and show that AQP2 recycles between the plasma membrane and intracellular vesicles via a dynamin-dependent endocytotic pathway. We propose that the IMP clusters previously associated with vasopressin action represent sites of dynamin-dependent, clathrin-mediated endocytosis in which AQP2 is concentrated before internalization.

The extrarhabdomeral cytoskeleton in photoreceptors of Diptera. II. Plasmalemmal undercoats

1984 ◽  
Vol 220 (1220) ◽  
pp. 353-359 ◽  
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Genetic Analysis ◽  
Freeze Fracture ◽  
Integral Membrane Proteins ◽  
Basal Region ◽  
Thin Sections ◽  
En Face ◽  
Thiol Proteases ◽  
Planar Membranes

The plasmalemmal undercoats of those regions of the photoreceptors of the blowfly Lucilia that flank the central extracellular space of each ommatidium are described from en face and transverse thin sections. Labile structures were stabilized before fixation for electron microscopy by using an inhibitor of thiol proteases, Ep-475, as described in the previous paper (Blest et al., Proc. R. Soc. Lond . B 220, 339-352, 1984). Membranes of R 1-6 are underlain by a closely associated, randomly organized filamentous meshwork. That of the basal region of R 7 is highly organized, and consists of very long, about 8 nm filaments running parallel to each other and to the longitudinal ommatidial axis; these ‘backbone’ filaments are tightly adherent to the plasma membrane, and are spaced some 190-200 nm apart. They are linked by abundant transverse filaments that form a reticulum between them. The degree of ordering of the reticulum in life is not clear, but some well-preserved profiles suggest that it may be high. Replicas obtained by the freeze-fracture technique show that extrarhabdomeral membranes have dense populations of intramembrane particles, just as they do in Drosophila where a genetic analysis has shown them to consist largely of rhodopsin. It is proposed as a working hypothesis that these planar membranes can be regarded as flat equivalents of the microvillar membranes, that some fraction of the integral membrane proteins may be immobilized by bonding to the plasmalemmal undercoat, and that the latter may help to constrain both the translational and rotational movements of rhodopsin molecules.

An electron microscopic study of vitellogenesis and egg membrane formation in Lytta nuttalli Say (ColeopterarMeloidae)

1970 ◽  
Vol 48 (4) ◽  
pp. 651-657 ◽  
Author(s):  
P. R. Sweeny ◽  
N. S. Church ◽  
J. G. Rempel ◽  
Wendy Frith
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Follicle Cells ◽  
Vitelline Membrane ◽  
Electron Microscopic ◽  
Yolk Formation ◽  
Membrane Formation ◽  
Electron Dense Material ◽  
Egg Membrane ◽  
Pass Through

Vitellogenesis and egg membrane formation in the terminal ovarian follicles of Lytta nuttatii were investigated by electron microscopy. Three kinds of yolk globules are produced. They apparently are composed predominantly of carbohydrates, lipids, and proteins, respectively. The "carbohydrate" and "lipid" yolk are assembled in the ooplasm, the former by rough endoplasmic reticulum and the latter by Golgi complexes. Their production begins early in oogenesis. "Proteid" yolk formation begins somewhat later. The "proteid" yolk globules evidently are formed from exfraovarian materials that pass through large spaces that develop between the follicular epithelial cells, then through the oocyte plasma membrane by pinocytosis. Fairly late in development, glycogen granules appear in the inner ooplasm. In the nearly fully grown follicle, the "membranous system" of the vitelline membrane is elaborated. It probably is formed largely from an electron-dense material of undetermined origin that accumulates outside the bases of the oocyte plasma membrane microvilli. Immediately after completion of the vitelline membrane, the chorion is laid down, presumably from dense globules of material produced by Golgi complexes in the follicle cells.

scholarly journals Teleost chloride cell. I. Response of pupfish Cyprinodon variegatus gill Na,K-ATPase and chloride cell fine structure to various high salinity environments.

1976 ◽  
Vol 70 (1) ◽  
pp. 144-156 ◽  
Author(s):  
K J Karnaky ◽  
S A Ernst ◽  
C W Philpott
Keyword(s):  
Cell Surface ◽  
Atpase Activity ◽  
High Salinity ◽  
Cell Structure ◽  
Chloride Cell ◽  
Salt Transport ◽  
Chloride Cells ◽  
Osmotic Gradient ◽  
Cyprinodon Variegatus ◽  
Very High

Certain euryhaline teleosts can tolerate media of very high salinity, i.e. greater than that of seawater itself. The osmotic gradient across the integument of these fish is very high and the key to their survival appears to be the enhanced ability of the gill to excrete excess NaCl. These fish provide an opportunity to study morphological and biochemical aspects of transepithelial salt secretion under conditions of vastly different transport rates. Since the cellular site of gill salt excretion is believed to be the "chloride cell" of the branchial epithelium and since the enzyme Na,K-ATPase has been implicated in salt transport in this and other secretory tissues, we have focused our attention on the differences in chloride cell structure and gill ATPase activity in the variegated pupfish Cyprinodon variegatus adapted to half-strength seawater (50% SW), seawater (100% SW), or double-stregth seawater (200% SW). The Na,K-ATPase activity in gill homogenates was 1.6 times greater in 100% SW. When 50% SW gills were compared to 100% SW gills, differences in chloride cell morphology were minimal. However, chloride cells from 200% SW displayed a marked hypertrophy and a striking increase in basal-lateral cell surface area. These results suggest that there are correlations among higher levels of osmotic stress, basal-lateral extensions of the cell surface, and the activity of the enzyme Na,K-ATPase.

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