scholarly journals Surface functions during mitosis. III. Quantitative analysis of ligand-receptor movement into the cleavage furrow: diffusion vs. flow.

1982 ◽  
Vol 93 (3) ◽  
pp. 950-960 ◽  
Author(s):  
D E Koppel ◽  
J M Oliver ◽  
R D Berlin
Keyword(s):  
Cell Shape ◽  
Single Cells ◽  
Effective Diffusion ◽  
Membrane Receptors ◽  
Cleavage Furrow ◽  
Receptor Complex ◽  
Con A ◽  
Surface Distribution ◽  
Lectin Receptor ◽  
Receptor Complexes

The surface distribution of concanavalin A (Con A) bound to cell membrane receptors varies dramatically as a function of mitotic phase. The lectin is distributed diffusely on cells labeled and observed between mid-prophase and early anaphase, whereas cells observed in late anaphase or telophase demonstrate a marked accumulation of Con A-receptor complexes over the developing cleavage furrow (Berlin, Oliver, and Walter. 1978. Cell. 15:327-341). In this report, we first use a system based on video intensification fluorescence microscopy to describe the simultaneous changes in cell shape and in lectin-receptor complex topography during progression of single cells through the mitotic cycle. The video analysis establishes that fluorescein succinyl Con A (F-S Con A)-receptor complex redistribution begins coincident with the first appearance of the cleavage furrow and is essentially complete within 2-3 min. This remarkable redistribution of surface fluorescence occurs during only a modest change in cell shape from a sphere to a belted cylinder. It reflects the translocation of complexes and not the accumulation of excess labeled membrane in the cleavage furrow: first, bound fluorescent cholera toxin which faithfully outlines the plasma membrane is not accumulated in the cleavage furrow, and, second, electron microscopy of peroxidase-Con A labeled cells undergoing cleavage shows that there is a high linear density of lectin within the furrow while Con A is virtually eliminated from the poles. The rate of surface movement of F-S Con A was quantitated by photon counting during a repetitive series of laser-excited fluorescence scans across dividing cells. Results were analyzed in terms of two alternative models of movement: a flow model in which complexes moved unidirectionally at constant velocity, and a diffusion model in which complexes could diffuse freely but were trapped at the cleavage furrow. According to these models, the observed rates of accumulation were attainable at either an effective flow velocity of approximately 1 micron/min, or an effective diffusion coefficient of approximately 10(-9) cm2/s. However, in separate experiments the lectin-receptor diffusion rate measured directly by the method of fluorescence recovery after photobleaching (FRAP) on metaphase cells was only approximately 10(-10) cm2/s. Most importantly, photobleaching experiments during the actual period of F-S Con A accumulation showed that lectin-receptor movement during cleavage occurs unidirectionally. These results rule out diffusion and make a process of oriented flow of ligand-receptor complexes the most likely mechanism for ligand-receptor accumulation in the cleavage furrow.

scholarly journals Signaling through the interleukin-4 and interleukin-13 receptor complexes regulates cholangiocyte TMEM16A expression and biliary secretion

2020 ◽  
Vol 318 (4) ◽  
pp. G763-G771
Author(s):  
Amal K. Dutta ◽  
Kristy Boggs ◽  
Al-karim Khimji ◽  
Yonas Getachew ◽  
Youxue Wang ◽  
...  
Keyword(s):  
Single Cells ◽  
Biliary Secretion ◽  
Interleukin 4 ◽  
Current Response ◽  
Receptor Complex ◽  
Regulatory Pathway ◽  
Bile Formation ◽  
Liver Disorders ◽  
Receptor Complexes ◽  
Insight Into

TMEM16A is a Ca2+-activated Cl− channel in the apical membrane of biliary epithelial cells, known as cholangiocytes, which contributes importantly to ductular bile formation. Whereas cholangiocyte TMEM16A activity is regulated by extracellular ATP-binding membrane purinergic receptors, channel expression is regulated by interleukin-4 (IL-4) through an unknown mechanism. Therefore, the aim of the present study was to identify the signaling pathways involved in TMEM16A expression and cholangiocyte secretion. Studies were performed in polarized normal rat cholangiocyte monolayers, human Mz-Cha-1 biliary cells, and cholangiocytes isolated from murine liver tissue. The results demonstrate that all the biliary models expressed the IL-4Rα/IL-13Rα1 receptor complex. Incubation of cholangiocytes with either IL-13 or IL-4 increased the expression of TMEM16A protein, which was associated with an increase in the magnitude of Ca2+-activated Cl− currents in response to ATP in single cells and the short-circuit current response in polarized monolayers. The IL-4- and IL-13-mediated increase in TMEM16A expression was also associated with an increase in STAT6 phosphorylation. Specific inhibition of JAK-3 inhibited the increase in TMEM16A expression and the IL-4-mediated increase in ATP-stimulated currents, whereas inhibition of STAT6 inhibited both IL-4- and IL-13-mediated increases in TMEM16A expression and ATP-stimulated secretion. These studies demonstrate that the cytokines IL-13 and IL-4 regulate the expression and function of biliary TMEM16A channels through a signaling pathway involving STAT6. Identification of this regulatory pathway provides new insight into biliary secretion and suggests new targets to enhance bile formation in the treatment of cholestatic liver disorders. NEW & NOTEWORTHY The Ca2+-activated Cl− channel transmembrane member 16A (TMEM16A) has emerged as an important regulator of biliary secretion and hence, ductular bile formation. The present studies represent the initial description of the regulation of TMEM16A expression in biliary epithelium. Identification of this regulatory pathway involving the IL-4 and IL-13 receptor complex and JAK-3 and STAT-6 signaling provides new insight into biliary secretion and suggests new therapeutic targets to enhance bile formation in the treatment of cholestatic liver disorders.

scholarly journals Correlation between movement of concanavalin A membrane receptors and cytolysis. A scanning electron microscopy study.

1977 ◽  
Vol 75 (2) ◽  
pp. 388-397 ◽  
Author(s):  
S Lustig ◽  
O Ascher ◽  
P Fishman ◽  
M Djaldetti ◽  
D H Pluznik
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Concanavalin A ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Membrane Receptors ◽  
Lateral Mobility ◽  
Con A ◽  
Lectin Receptor ◽  
Scanning Electron

The present study was undertaken to test whether cytolysis induced by Concanavalin A (Con A) requires lateral mobility of membranal lectin receptor sites into caps. Treatment of interphase murine mastocytoma cells with 10(-4) M colchicine promoted cap formation by Con A in about 30% of the cells, followed by cytolysis. Pretreatment of the cells with NaN3, low temperature, or glutaraldehyde decreased the degree of capping and, to the same extent, the degree of cytolysis. The addition of antibodies to cells bound with Con A increased the appearance of capping and cytolysis. A linear relationship with a high correlation coefficient exists between the degree of capping and cytolysis, suggesting that lateral mobility of membrane Con A receptors is required for cytolysis by the lectin. The process of cap formation by Con A up to the stage of cytolysis was followed by scanning electron microscopy.

scholarly journals Microtubules and cyclic amp in human leukocytes: on the order of things

1978 ◽  
Vol 77 (3) ◽  
pp. 881-886 ◽  
Author(s):  
SE Malawista ◽  
JM Oliver ◽  
SA Rudolph
Keyword(s):  
Cyclic Amp ◽  
Phosphodiesterase Inhibitor ◽  
Microtubule Assembly ◽  
Con A ◽  
Human Leukocytes ◽  
Lectin Receptor ◽  
Receptor Complexes ◽  
Hormone Sensitive ◽  
Cytoplasmic Microtubules ◽  
Induced Changes

We have shown previously that the β-adrenergic agonist isoproterenol (2μM) and the phosphodiesterase inhibitor isobutylmethylxanthine (1 mM) produce a much greater increase in cyclic AMP in human leukocytes that have been pretreated with colchicine (or with other agents that affect microtubule assembly) than in control leukocytes. The effects of colchicines were both time- and dose-dependant. These and other data suggested that the generation of cyclic AMP is normally restricted by an intact system of cytoplasmic microtubules. If so, then the same time and dose dependencies might apply to other colchicines-induced changes in leukocyte function. We have now assayed the distribution of concanavalin A (Con A)-receptor complexes on the leukocyte membrane, taking into account that leukocytes competent to assemble microtubules show a uniform distribution of surface- bound Con A whereas microtubule-deficient cells accumulate Con A in surface caps. We have found that the effect of colchicine on capping is also both time- and dose dependent, and that the dose-response relationships conform to those required to increase cyclic AMP levels. These findings provide further evidence that both colchicine-induced Con-A capping and colchicine- induced cyclic AMP generation depend upon the relaxation of constraints normally imposed by cytoplasmic microtubules upon the plasma membrane, which limit, respectively, lateral mobility of the lectin-receptor complexes, and expression of hormone-sensitive adenylate cyclase. Moreover, colchicine-induced Con-A cap formation is not affected even by very large changes in leukocyte cyclic AMP levels. Thus, elevated cyclic AMP levels do not appear to promote the dissolution of microtubules; rather, the dissolution of microtubules permits the generation of increased amounts of cyclic AMP.

scholarly journals Microtubule and microfilament rearrangements during capping of concanavalin A receptors on cultured ovarian granulosa cells.

1977 ◽  
Vol 73 (1) ◽  
pp. 111-127 ◽  
Author(s):  
D F Albertini ◽  
E Anderson
Keyword(s):  
Granulosa Cells ◽  
Concanavalin A ◽  
Freeze Fracture ◽  
Con A ◽  
Lectin Receptor ◽  
Receptor Complexes ◽  
Thick Filaments ◽  
Section Electron ◽  
Electron Microscope Analysis ◽  
Endocytic Vesicles

Thin-section electron microscope analysis of rat and rabbit-cultured granulosa cells treated with concanavalin A (Con A) at 37 degrees C revealed coordinated changes in the cytoplasmic disposition of microfilaments, thick filaments, and microtubules during cap formation and internalization of lectin-receptor complexes. Con A-receptor clustering is accompanied by an accumulation of subplasmalemmal microfilaments which assemble into a loosely woven ring as patches of receptor move centrally on the cell surface. Periodic densities appear in the microfilament ring which becomes reduced in diameter as patches coalesce to form a single central cap. Microtubules and thick filaments emerge associated with the capped membrane. Capping is followed by endocytosis of the con A-receptor complexes. During this process, the microfilament ring is displaced basally into the cytoplasm and endocytic vesicles are transported to the paranuclear Golgi complex along microtubules and thick filaments. Eventually, these vesicles aggregate near the cell center where they are embedded in a dense meshwork of thick filaments. Freeze-fracture analysis of Con A-capped granulosa cells revealed no alteration in the arrangement of peripheral intramembrane particles but large, smooth domains were conspicuous in the capped region of the plasma membrane. The data are discussed with reference to the participation of microtubules and microfilaments in the capping process.

scholarly journals Isolation of concanavalin a caps during various stages of formation and their association with actin and myosin

1979 ◽  
Vol 80 (3) ◽  
pp. 751-758 ◽  
Author(s):  
J Condeelis
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Concanavalin A ◽  
Specific Binding ◽  
Lectin Binding ◽  
Metabolic Energy ◽  
Con A ◽  
Thin Filaments ◽  
Lectin Receptor ◽  
Receptor Complexes

Regions of plasma membrane of dictyostelium discoideum amoebae that contain concanavalin A (Con A)-receptor complexes are more resistant to disruption by Triton X-100. This resistance makes possible the isolation of Con A-associated membrane fragments in sufficient quantity and homogeneity to permit the direct biochemical and ultrastructural study of receptor-cytoskeletal interactions across the cell membrane. After specific binding of Con A to the cell surface, a large amount of the cell's actin and myosin copurifies with the plasma membrane fragments. Myosin is more loosely bound to the isolated membranes that actin and is efficiently removed by treating membranes with ATP and low ionic strength. If cells are not lysed immediately after lectin binding, all of the Con A that is bound to the cell surface is swept into a cap in a process requiring metabolic energy. When cells are lysed at different stages of cap formation, the amount of actin and myosin that copurifies with the isolated membranes remains the same. Thick and thin filaments that are attached to the protoplasmic surface of the isolated membranes underlie lectin-receptor complexes during all stages of cap formation. Once the cap is complete, the amount of actin and myosin that tightly bound to the plasma membrane is concentrated into the cap along with the Con A-receptor complexes. These results suggest that the ATP-dependent sliding of membrane-associated actin and myosin filaments is responsible for the accumulation of Con A-receptor complexes into a cap on the cell surface.

Structure and function of the CD94 C-type lectin receptor complex involved in recognition of HLA class I molecules

1997 ◽  
Vol 155 (1) ◽  
pp. 165-174 ◽  
Author(s):  
Miguel Lopez-Botet ◽  
Juan J. Perez-Villar ◽  
Marta Carretero ◽  
Antonio Rodriguez ◽  
Ignacio Melero ◽  
...  
Keyword(s):  
Hla Class I ◽  
Structure And Function ◽  
Class I ◽  
Receptor Complex ◽  
Lectin Receptor ◽  
Hla Class I Molecules ◽  
And Function

scholarly journals An analysis of lectin-initiated cell agglutination in a series of CHO subclones which respond morphologically to growth in dibutyryl cyclic AMP.

1976 ◽  
Vol 70 (1) ◽  
pp. 204-216 ◽  
Author(s):  
J van Veen ◽  
R M Roberts ◽  
K D Noonan
Keyword(s):  
Surface Membrane ◽  
Con A ◽  
Cell Agglutination ◽  
Lectin Receptors ◽  
Lectin Receptor ◽  
Free Mobility ◽  
Receptor Sites ◽  
Protein And Rna Synthesis ◽  
A Cell ◽  
Membrane Components

We have investigated the molecular basis of the agglutinability of CHO subclones which respond differentially in terms of morphology and surface architecture in the presence of dB-cAMP in the medium. We have demonstrated that the agglutinability of these subclones with both wheat germ agglutinin (WGA) and concanavalin A (Con A) probably depends on the free lateral mobility of the lectin receptor sites in the plane of the membrane. The nonagglutinable surface architecture seems to depend on the presence in the membrane of a protease-labile peptide(s), which appears to be distinct from the lectin receptors, as well as on continuous protein and RNA synthesis. This dependence on continuous transcription and translation may be related to the maintenance of the protease-labile peptide(s) in such a state as to restrict mobility of the lectin receptors. The surface architecture defined as nonagglutinable also depends on the state of polymerization of the intracellular microtubules and microfilaments. It is suggested that these microskeletal elements serve to anchor the lectin receptors in such a manner as to restrict their mobility and thereby reduce the relative agglutinability of a cell line. We suggest that control of the free mobility of both the Con A and WGA receptor sites is dependent on two constraints, one applied by protease-labile ("surface") membrane components and the other by components of the intracellular microskeletal system.

scholarly journals The alpha 1-alpha 6 subunits of integrins are characteristically expressed in distinct segments of developing and adult human nephron.

1990 ◽  
Vol 111 (3) ◽  
pp. 1245-1254 ◽  
Author(s):  
M Korhonen ◽  
J Ylänne ◽  
L Laitinen ◽  
I Virtanen
Keyword(s):  
Human Kidney ◽  
Membrane Receptors ◽  
Minor Role ◽  
Integrin Subunit ◽  
Fibronectin Receptor ◽  
Receptor Complexes ◽  
Nephron Segments ◽  
Alpha Subunits ◽  
Adult Human ◽  
Distal Tubules

We studied the distribution of the alpha 1-alpha 6 subunits of beta 1 integrins in developing and adult human kidney using a panel of mAbs in indirect immunofluorescence microscopy. Uninduced mesenchyme displayed a diffuse immunoreactivity for only the alpha 1 integrin subunit. At the S-shaped body stage of nephron development, several of the alpha subunits were characteristically expressed in distinct fetal nephron segments, and the pattern was retained also in the adult nephron. Thus, the alpha 1 subunit was characteristically expressed in mesangial and endothelial cells, the alpha 2 in glomerular endothelium and distal tubules, the alpha 3 in podocytes, Bowman's capsule, and distal tubules, and the alpha 6 subunit basally in all tubules, and only transiently in podocytes during development. Unlike the alpha 3 and alpha 6 subunits, the alpha 2 subunit displayed an overall cell surface distribution in distal tubules. It was also distinctly expressed in glomerular endothelia during glomerulogenesis. The beta 4 subunit was expressed only in fetal collecting ducts, and hence the alpha 6 subunit seems to be complexed with the beta 1 rather than beta 4 subunit in human kidney. Of the two fibronectin receptor alpha subunits, alpha 4 and alpha 5, only the latter was expressed, confined to endothelia of developing and adult blood vessels, suggesting that these receptor complexes play a minor role during nephrogenesis. The present results suggest that distinct integrins play a role during differentiation of specific nephron segments. They also indicate that alpha 3 beta 1 and alpha 6 beta 1 integrin complexes may function as basement membrane receptors in podocytes and tubular epithelial cells.

scholarly journals Extracellular pyridine nucleotides trigger plant systemic immunity through a lectin receptor kinase/BAK1 complex

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Chenggang Wang ◽  
Xiaoen Huang ◽  
Qi Li ◽  
Yanping Zhang ◽  
Jian-Liang Li ◽  
...  
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Systemic Acquired Resistance ◽  
Plant Immunity ◽  
Acquired Resistance ◽  
Receptor Complex ◽  
Pyridine Nucleotides ◽  
Receptor Kinase ◽  
Systemic Immunity ◽  
Lectin Receptor

Abstract Systemic acquired resistance (SAR) is a long-lasting broad-spectrum plant immunity induced by mobile signals produced in the local leaves where the initial infection occurs. Although multiple structurally unrelated signals have been proposed, the mechanisms responsible for perception of these signals in the systemic leaves are unknown. Here, we show that exogenously applied nicotinamide adenine dinucleotide (NAD+) moves systemically and induces systemic immunity. We demonstrate that the lectin receptor kinase (LecRK), LecRK-VI.2, is a potential receptor for extracellular NAD+ (eNAD+) and NAD+ phosphate (eNADP+) and plays a central role in biological induction of SAR. LecRK-VI.2 constitutively associates with BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1) in vivo. Furthermore, BAK1 and its homolog BAK1-LIKE1 are required for eNAD(P)+ signaling and SAR, and the kinase activities of LecR-VI.2 and BAK1 are indispensable to their function in SAR. Our results indicate that eNAD+ is a putative mobile signal, which triggers SAR through its receptor complex LecRK-VI.2/BAK1 in Arabidopsis thaliana.

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