Specific binding of [3H]oxytocin in the female rat brain

1983 ◽  
Vol 61 (9) ◽  
pp. 989-995 ◽  
Author(s):  
B. M. Ferrier ◽  
S.A. McClorry ◽  
A. W. Cochrane
Keyword(s):  
Plasma Membrane ◽  
Limbic System ◽  
Microsomal Fraction ◽  
Specific Binding ◽  
Cell Types ◽  
Time Dependent ◽  
Female Rat ◽  
Ph Optimum ◽  
Rat Tissue ◽  
Different Cell Types

Because of demonstrated effects of oxytocin on some limbic system mediated behaviours, the specific binding of [3H]oxytocin to a plasma membrane containing fraction of rat limbic tissue has been studied. The binding of the microsomal fraction of estrogenized, female rat tissue was time dependent and saturable, with a Bmax of 2.5 × 10−l3 moles per milligram of protein and an apparent KD of 3.53 × 10−8 M, and appeared to show positive cooperativity. The pH optimum of the binding was 6.0, close to the pH optimum for oxytocin – neurophysin binding; however, other results show the two types of binding to be different. The microsomal fraction did not appreciably degrade oxytocin under the conditions used for [3H]oxytocin binding. The distribution in limbic tissue of oxytocin-degrading activity and of individual enzymes capable of degrading oxytocin has been examined and an interplay of enzymes concentrated in different cell types is proposed.

Fine-Structural Localization of Adenosine Triphosphatase in the Rectum of Calliphora

1968 ◽  
Vol 3 (1) ◽  
pp. 17-32
Author(s):  
M. J. BERRIDGE ◽  
B. L. GUPTA
Keyword(s):  
Plasma Membrane ◽  
Adenosine Triphosphatase ◽  
Plasma Membranes ◽  
Fluid Transport ◽  
Microsomal Fraction ◽  
Adenosine Diphosphate ◽  
Structural Basis ◽  
Osmotic Gradient ◽  
Ph Optimum ◽  
Structural Localization

Adenosine triphosphatase (ATPase) activity in the rectal papillae of Calliphora has been studied by biochemical and histochemical techniques. The microsomal fraction contained a Mg2+-activated ATPase with a pH optimum of 8.0. The enzyme was not stimulated by the addition of Na+ plus K+ and was insensitive to ouabain. Histochemical studies using modifications of the Wachstein-Meisel method showed that at pH 7.2 this Mg2+-activated ATPase was specifically localized on the intracellular surface of the lateral plasma membranes. A similar though less intense reaction was obtained with adenosine diphosphate and inosine triphosphate, but not with guanosine triphosphate, uridine triphosphate or β-glycerophosphate as substrates. At an acid pH (6.6-6.8), very little reaction occurred on the lateral plasma membrane but some reaction product was present in mitochondria and nuclei. Very little enzyme activity was found in the flattened rectal epithelium. These results are discussed in relation to the available data on transport ATPases and on the structural basis of fluid transport by rectal papillae. It is proposed that the ATPase localized on the stacks of lateral plasma membrane may be involved with ion secretion into the intercellular spaces to create the osmotic gradient necessary to extract water from the lumen.

scholarly journals Recent Experiments Support a Microemulsion Origin of Plasma Membrane Domains: Dependence of Domain Size on Physical Parameters

Membranes ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 167
Author(s):  
David W. Allender ◽  
M. Schick
Keyword(s):  
Plasma Membrane ◽  
Domain Size ◽  
Cell Types ◽  
Physical Parameters ◽  
Spontaneous Curvature ◽  
Membrane Domains ◽  
Physical Origin ◽  
Unsaturated Lipids ◽  
Bending Modulus ◽  
Different Cell Types

It is widely, but not universally, believed that the lipids of the plasma membrane are not uniformly distributed, but that “rafts” of sphingolipids and cholesterol float in a “sea” of unsaturated lipids. The physical origin of such heterogeneities is often attributed to a phase coexistence between the two different domains. We argue that this explanation is untenable for several reasons. Further, we note that the results of recent experiments are inconsistent with this picture. However, they are quite consistent with an alternate explanation, namely, that the plasma membrane is a microemulsion of the two kinds of regions. To show this, we briefly review a simplified version of this theory and its phase diagram. We also explicate the dependence of the predicted domain size on four physical parameters. They are the energy cost of gradients in the composition, the spontaneous curvature of the membrane, its bending modulus and its surface tension. Taking values of the latter two from experiment, we obtain domain sizes for several different cell types that vary from 58 to 88 nm.

Comparative studies of insulin binding to receptor from adipocytes, hepatocytes, monocytes and erythrocytes from the pig

1988 ◽  
Vol 118 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Elisabeth Hjøllund ◽  
Bjørn Richelsen ◽  
Oluf Pedersen
Keyword(s):  
Steady State ◽  
Receptor Binding ◽  
Specific Binding ◽  
Insulin Binding ◽  
Cell Types ◽  
Target Cells ◽  
Suitable Model ◽  
The Individual ◽  
Different Cell Types ◽  
Specific Insulin

Abstract. We have described the receptor binding of A 14-labelled [125I]insulin to viable adipocytes, hepatocytes, monocytes and erythrocytes from the pig. For all cell types the binding was of high affinity, specific for insulin, the non-specific binding low and degradation of insulin in the medium was minimal. At 24°C, steady state insulin binding was achieved in all four cell types. At 37°C, steady state insulin binding could be measured to adipocytes and hepatocytes. Specific insulin binding levels and receptor affinity for blood and fat cells from the pig are comparable to that in human cells, whereas differences, especially according to affinity, exist between pig and rat cell insulin receptor binding. It is therefore concluded that the pig is a more suitable model for studies of insulin binding in man than rodents. Finally, no correlations between the individual binding levels to the different cell types were observed. Hence, measurement of insulin binding to the easier available blood cells cannot replace studies of insulin binding to target cells of insulin.

scholarly journals Membrane mechanics govern spatiotemporal heterogeneity of endocytic clathrin coat dynamics

2017 ◽  
Vol 28 (24) ◽  
pp. 3480-3488 ◽  
Author(s):  
N. M. Willy ◽  
J. P. Ferguson ◽  
S. D. Huber ◽  
S. P. Heidotting ◽  
E. Aygün ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Morphological Changes ◽  
Cell Types ◽  
Membrane Tension ◽  
Membrane Mechanics ◽  
Cellular Processes ◽  
Spatiotemporal Heterogeneity ◽  
Multicellular Organisms ◽  
Different Cell Types

Dynamics of endocytic clathrin-coated structures can be remarkably divergent across different cell types, cells within the same culture, or even distinct surfaces of the same cell. The origin of this astounding heterogeneity remains to be elucidated. Here we show that cellular processes associated with changes in effective plasma membrane tension induce significant spatiotemporal alterations in endocytic clathrin coat dynamics. Spatiotemporal heterogeneity of clathrin coat dynamics is also observed during morphological changes taking place within developing multicellular organisms. These findings suggest that tension gradients can lead to patterning and differentiation of tissues through mechanoregulation of clathrin-mediated endocytosis.

scholarly journals Detection of receptors for sulfated polysaccharides in human placenta by biotinylated probes.

1988 ◽  
Vol 36 (9) ◽  
pp. 1097-1102 ◽  
Author(s):  
P L Debbage ◽  
W Lange ◽  
T Hellmann ◽  
H J Gabius
Keyword(s):  
Developmental Stage ◽  
Human Placenta ◽  
Binding Sites ◽  
Dermatan Sulfate ◽  
Specific Binding ◽  
Cell Types ◽  
Sulfated Polysaccharides ◽  
Stage Of Development ◽  
Different Cell Types ◽  
Biotinylated Probes

Histochemical detection of binding sites for sulfated polysaccharides believed to be important mediators within recognitive interactions was carried out by application of biotinylated probes such as heparin, native and desulfated fucoidan, dermatan sulfate, and two types of carrageenans. The probes were derivatized by mild cyanogen bromide activation and subsequent aminoalkylation to allow incorporation of biotin, inserted with an epsilon-aminocaproic acid spacer to reduce charge-related and steric impediments. Specific labeling could be detected in different cell types of human placenta, dependent on the developmental stage. Sulfated polysaccharides bound predominantly to leucocytes in full-term placenta, whereas demonstration of specific binding sites in decidua, syncytiotrophoblasts, and cytotrophoblasts was restricted primarily to heparin and, less intensely, fucoidan, although not desulfated fucoidan. Heparin binding in the placenta after 8 weeks of gestation was reduced for epithelia that, at this stage of development, revealed carrageenan binding sites. Fucoidan binding was at this developmental stage measurable only for leucocytes. These results provide definite histochemical evidence for the presence and developmental regulation of expression of receptors for sulfated polysaccharides in different cell types of human placenta.

Time-Dependent Determination of HF Formation in LiPF6 -Containing Electrolytes in Different Cell Types by Spectroscopic Ellipsometry

2013 ◽  
Vol 50 (1) ◽  
pp. 27-30 ◽  
Author(s):  
S. F. Lux ◽  
I. T. Lucas ◽  
J. S. Chevalier ◽  
T. J. Richardson ◽  
R. M. Kostecki
Keyword(s):  
Spectroscopic Ellipsometry ◽  
Cell Types ◽  
Time Dependent ◽  
Different Cell Types

Proteins involved in the attachment of actin to the plasma membrane

1982 ◽  
Vol 299 (1095) ◽  
pp. 291-299 ◽  
Keyword(s):  
Plasma Membrane ◽  
Actin Filaments ◽  
Cell Types ◽  
Brain Protein ◽  
Cultured Fibroblasts ◽  
Microfilament Bundles ◽  
Different Cell Types ◽  
Adhesion Plaque ◽  
The Brain

Proteins that may be involved in two types of actin-membrane association are discussed. The first set includes α-actinin, vinculin, fimbrin and a new cytoskeletal protein that are all concentrated in adhesion plaques, those regions of cultured fibroblasts where bundles of actin microfilaments terminate and where the plasma membrane comes close to the underlying substrate. The properties of non-muscle α-actinin suggest that it functions to cross-link actin filaments and thereby stabilize microfilament bundles rather than functioning in their attachment to the membrane. Fimbrin also appears to be involved in bundling of filaments rather than in attachment. In contrast, vinculin binds to the ends of actin filaments in vitro and is probably the best candidate for a role in the attachment of actin to membranes at the adhesion plaque. The discovery of a new protein, 215k, of unknown function, in the adhesion plaque suggests that many more proteins remain to be identified in this region. Attachment of actin filaments to other regions of the plasma membrane is also considered and a protein is described that seems to be a spectrin homologue in brain and other tissues. The brain protein resembles erythrocyte spectrin in its physical properties, in binding actin, in being associated with cell membranes and in crossreacting immunologically. We suggest that the brain protein and erythrocyte spectrin both belong to a family of related proteins (the spectrins) which function in the attachment of actin to membranes in many different cell types.

scholarly journals Synemin and vimentin are components of intermediate filaments in avian erythrocytes

1982 ◽  
Vol 92 (2) ◽  
pp. 299-312 ◽  
Author(s):  
BL Granger ◽  
EA Repasky ◽  
E Lazarides
Keyword(s):  
Plasma Membrane ◽  
Intermediate Filaments ◽  
Plasma Membranes ◽  
Cell Types ◽  
Special Role ◽  
Thin Sections ◽  
Avian Erythrocytes ◽  
Nonionic Detergent ◽  
Weight Protein ◽  
Different Cell Types

Synemin, a high-molecular-weight protein associated with intermediate filaments in muscle, and vimentin, an intermediate-filament subunit found in many different cell types, have been identified by immunologic and electrophoretic criteria as components of intermediate filaments in mature avian erythrocytes. Desmin, the predominant subunit of intermediate filaments in muscle, has not been detected in these cells. Two dimensional immunoautoradiography of proteolytic fragments of synemin and vimentin demonstates that the erythrocyte proteins are highly homologous, if not identical, to their muscle counterparts. Double immunoflurorescence reaveals that erythrocyte synemin and vimentin co-localize in a cytoplasmic network of sinuous filaments that extends from the nucleus to the plasma membrane and resists aggregation by colcemid. Erythrocytes that are attached to glass cover slips can be sonicated to remove nuclei and nonadherent regions of the plasma membrane; this leaves elliptical patches of adherent membrane that retain mats of vimentin- and synemin-containing intermediate filaments, as seen by immunofluorescence and rotary shadowing. Similarly, mechanical enucleation of erythrocyte ghosts in suspension allows isolation of plasma membranes that retain a significant fraction of the synemin and vimentin, as assayed by electrophoresis, and intermediate filaments, as seen in thin sections. Both synemin and vimentin remain insoluble along with spectrin and actin, in solutions containing nonionic detergent and high salt. However, brief exposure of isolated membrane to distilled water releases the synemin and vimentin together in nearly pure form, before the release of significant amounts of spectrin and actin. These data suggest that avian erythrocyte intermeditate filaments are somehow anchored to the plasma membrane; erythrocytes may thus provide a simple system for the study of intermediate filaments and their mode of interaction with membranes. In addition, these data, in conjunction with previous data from muscle, indicate that synemin is capable of associating with either desmin or vimentin and may thus perform a special role in the structure or function of intermediate filaments in erythrocytes as well as muscle.

scholarly journals Recent Experiments Support an Emulsion Origin of Plasma Membrane Domains: Dependence of Domain Size on Physical Parameters

2020 ◽  
Author(s):  
David W. Allender ◽  
M. Schick
Keyword(s):  
Plasma Membrane ◽  
Domain Size ◽  
Cell Types ◽  
Physical Parameters ◽  
Spontaneous Curvature ◽  
Membrane Domains ◽  
Physical Origin ◽  
Unsaturated Lipids ◽  
Bending Modulus ◽  
Different Cell Types

It is widely, but not universally, believed that the lipids of the plasma membrane are not uniformly distributed, but that "rafts'' of sphingolipids and cholesterol float in a "sea'' of unsaturated lipids. The physical origin of such heterogeneities is often attributed to a phase coexistence between the two different domains. We argue that this explanation is untenable for several reasons. Further we note that the results of recent experiments are inconsistent with this picture. However they are quite consistent with an alternate explanation, namely that the plasma membrane is an emulsion of the two kinds of regions. To show this, we briefly review a simplified version of this theory and its phase diagram. We also explicate the dependence of the predicted domain size on four physical parameters. Among them are the spontaneous curvature of the membrane and its bending modulus and surface tension. Taking values of the latter two from experiment, we obtain domain sizes for several different cell types that vary from 58 to 88 nm.

scholarly journals S-acylation of Orai1 regulates store-operated Ca2+ entry

2021 ◽  
Vol 135 (5) ◽  
Author(s):  
Savannah J. West ◽  
Goutham Kodakandla ◽  
Qioachu Wang ◽  
Ritika Tewari ◽  
Michael X. Zhu ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Cell Types ◽  
Central Component ◽  
Channel Activation ◽  
Crac Channels ◽  
Store Depletion ◽  
Crac Channel ◽  
Underlying Mechanisms ◽  
Different Cell Types

ABSTRACT Store-operated Ca2+ entry is a central component of intracellular Ca2+ signaling pathways. The Ca2+ release-activated channel (CRAC) mediates store-operated Ca2+ entry in many different cell types. The CRAC channel is composed of the plasma membrane (PM)-localized Orai1 channel and endoplasmic reticulum (ER)-localized STIM1 Ca2+ sensor. Upon ER Ca2+ store depletion, Orai1 and STIM1 form complexes at ER–PM junctions, leading to the formation of activated CRAC channels. Although the importance of CRAC channels is well described, the underlying mechanisms that regulate the recruitment of Orai1 to ER–PM junctions are not fully understood. Here, we describe the rapid and transient S-acylation of Orai1. Using biochemical approaches, we show that Orai1 is rapidly S-acylated at cysteine 143 upon ER Ca2+ store depletion. Importantly, S-acylation of cysteine 143 is required for Orai1-mediated Ca2+ entry and recruitment to STIM1 puncta. We conclude that store depletion-induced S-acylation of Orai1 is necessary for recruitment to ER–PM junctions, subsequent binding to STIM1 and channel activation.

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