scholarly journals Organization of desmosomal plaque proteins in cells growing at low calcium concentrations.

1988 ◽  
Vol 107 (3) ◽  
pp. 1049-1063 ◽  
Author(s):  
R Duden ◽  
W W Franke
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cell ◽  
Cell Cultures ◽  
Membrane Domains ◽  
Marker Protein ◽  
Cell Dissociation ◽  
Transmembrane Glycoprotein ◽  
Primary Mouse ◽  
Mouse Keratinocytes ◽  
Normal Calcium

Desmosomes are not formed in epithelial cell cultures growing in media with low (less than or equal to 0.1 mM) concentrations of Ca2+ (LCM) but appear rapidly upon shift to media of normal calcium concentrations (NCM). Previous authors using immunolocalization of desmoplakin, a marker protein for the desmosomal plaque, in LCM-grown cells have interpreted positively stained, dense, cytoplasmic aggregates on intermediate filaments (IF) bundles as preformed plaque units which upon NCM shift would move to the plasma membrane and contribute to desmosome formation. Studying various cell cultures, including primary mouse keratinocytes and human A-431 cells, we show that most, probably all, desmoplakin-positive aggregates in LCM-grown cells are associated with membranous structures, mostly vesicles, and also contain other desmosomal markers, including desmoglein, a transmembrane glycoprotein. We interpret such vesicles as residual desmosome-derived domains endocytosed upon cell dissociation. Only keratinocytes grown for long times (2-4 wk) in LCM are practically free from such vesicles. In addition, we demonstrate that certain cells such as A-431 cells, when passaged in LCM and in the absence of stable junctions, are able to continually assemble "half-desmosomes" on the plasma membrane which in turn can be endocytosed as plaque-bearing vesicles. We also show that in LCM the synthesis of several desmosomal proteins (desmoplakins I and II, plakoglobin, desmoglein, "band 6 protein") continues and that most of the plaque protein, desmoplakin, is diffusely spread over the cytoplasm, apparently in a soluble monodisperse form of approximately 9S. From our results we propose that the plaque proteins occur in small, discrete, diffusible entities in the cytoplasm, in concentrations that are relatively high in LCM and low in NCM, from which they assemble directly, i.e., without intermediate precursor aggregates on IFs in the cytoplasm, on certain plasma membrane domains in a Ca2+ dependent process.

An H+-ATPase in opposite plasma membrane domains in kidney epithelial cell subpopulations

Nature ◽  
1988 ◽  
Vol 331 (6157) ◽  
pp. 622-624 ◽  
Author(s):  
Dennis Brown ◽  
Sheldon Hirscht ◽  
Stephen Gluck
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cell ◽  
Membrane Domains ◽  
Kidney Epithelial Cell ◽  
Plasma Membrane Domains ◽  
Cell Subpopulations

CD44 exhibits a cell type dependent interaction with triton X-100 insoluble, lipid rich, plasma membrane domains

1995 ◽  
Vol 108 (9) ◽  
pp. 3127-3135 ◽  
Author(s):  
S.J. Neame ◽  
C.R. Uff ◽  
H. Sheikh ◽  
S.C. Wheatley ◽  
C.M. Isacke
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Transmembrane Domain ◽  
Direct Interaction ◽  
Membrane Domains ◽  
Cell Type ◽  
Transmembrane Glycoprotein ◽  
Morphological Studies ◽  
Plasma Membrane Domains ◽  
Triton X

CD44 is an abundant, widely expressed transmembrane glycoprotein which can act as a receptor for the extracellular matrix glycosaminoglycan, hyaluronan. Biochemical and morphological studies have demonstrated that in fibroblasts a significant of the CD44 population is resistant to Triton X-100 extraction and that the detergent insoluble protein is co-localized with components of the cortical cytoskeleton. Surprisingly, this distribution is not abrogated upon deletion of the CD44 cytoplasmic tail indicating that mechanisms other than a direct interaction with the cytoskeleton can regulate CD44. In this manuscript, the mechanisms underlying this detergent-insoluble association are further investigated. There was no evidence that the Triton X-100 insolubility of CD44 resulted from homotypic aggregation, an association with hyaluronan or from a direct, or indirect, association with the cytoskeleton. Instead, evidence is presented that the detergent insolubility of fibroblast CD44 at 4 degrees C results from an association of the CD44 transmembrane domain with Triton X-100 resistant, lipid rich, plasma membrane domains. The proportion of the CD44 found in these Triton X-100 insoluble structures is dependent upon cell type and cannot be altered by changing cell motility or extracellular matrix associations. These studies provide evidence for a novel mechanism regulating this adhesion protein in the plasma membrane.

scholarly journals Induction of caveolin during adipogenesis and association of GLUT4 with caveolin-rich vesicles.

1994 ◽  
Vol 127 (5) ◽  
pp. 1233-1243 ◽  
Author(s):  
P E Scherer ◽  
M P Lisanti ◽  
G Baldini ◽  
M Sargiacomo ◽  
C C Mastick ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Glucose Transporter ◽  
Protein Composition ◽  
Principal Component ◽  
Low Density ◽  
Membrane Domains ◽  
Marker Protein ◽  
Phosphorylated Protein ◽  
Glucose Transporter Glut4 ◽  
Stimulation Of

Caveolae, also termed plasmalemmal vesicles, are small, flask-shaped, non-clathrin-coated invaginations of the plasma membrane. Caveolin is a principal component of the filaments that make up the striated coat of caveolae. Using caveolin as a marker protein for the organelle, we found that adipose tissue is the single most abundant source of caveolae identified thus far. Caveolin mRNA and protein are strongly induced during differentiation of 3T3-L1 fibroblasts to adipocytes; during adipogenesis there is also a dramatic increase in the complexity of the protein composition of caveolin-rich membrane domains. About 10-15% of the insulin-responsive glucose transporter GLUT4 is found in this caveolin-rich fraction, and immuno-isolated vesicles containing GLUT4 also contain caveolin. However, in non-stimulated adipocytes the majority of caveolin fractionates with the plasma membrane, while most GLUT4 associates with low-density microsomes. Upon addition of insulin to 3T3-L1 adipocytes, there is a significant increase in the amount of GLUT4 associated with caveolin-rich membrane domains, an increase in the amount of caveolin associated with the plasma membrane, and a decrease in the amount of caveolin associated with low-density microsomes. Caveolin does not undergo a change in phosphorylation upon stimulation of 3T3-L1 adipocytes with insulin. However, after treatment with insulin it is associated with a 32-kD phosphorylated protein. Caveolae thus may play an important role in the vesicular transport of GLUT4 to or from the plasma membrane. 3T3-L1 adipocytes offer an attractive system to study the function of caveolae in several cellular trafficking and signaling events.

Membrane microdomains: lessons from microscopy

1995 ◽  
Vol 53 ◽  
pp. 776-777
Author(s):  
J.M. Robinson ◽  
J.M Oliver
Keyword(s):  
Spatial Distribution ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Plasma Membranes ◽  
Cell Types ◽  
Imaging Modalities ◽  
Membrane Microdomains ◽  
Membrane Domains ◽  
Lateral Heterogeneity ◽  
Functional Importance

Specialized regions of plasma membranes displaying lateral heterogeneity are the focus of this Symposium. Specialized membrane domains are known for certain cell types such as differentiated epithelial cells where lateral heterogeneity in lipids and proteins exists between the apical and basolateral portions of the plasma membrane. Lateral heterogeneity and the presence of microdomains in membranes that are uniform in appearance have been more difficult to establish. Nonetheless a number of studies have provided evidence for membrane microdomains and indicated a functional importance for these structures.This symposium will focus on the use of various imaging modalities and related approaches to define membrane microdomains in a number of cell types. The importance of existing as well as emerging imaging technologies for use in the elucidation of membrane microdomains will be highlighted. The organization of membrane microdomains in terms of dimensions and spatial distribution is of considerable interest and will be addressed in this Symposium.

scholarly journals CD133 Expression in the Nucleus Is Associated with Endometrial Carcinoma Staging and Tumor Angioinvasion

2021 ◽  
Vol 10 (10) ◽  
pp. 2144
Author(s):  
Milosz Pietrus ◽  
Kazimierz Pitynski ◽  
Marcin Waligora ◽  
Katarzyna Milian-Ciesielska ◽  
Monika Bialon ◽  
...  
Keyword(s):  
Endometrial Cancer ◽  
Plasma Membrane ◽  
Tumor Progression ◽  
Endometrial Carcinoma ◽  
Molecular Level ◽  
Risk Group ◽  
High Risk Group ◽  
Cd133 Expression ◽  
Transmembrane Glycoprotein ◽  
The Impact

Background: (1) Endometrial cancer is one of the most common cancers affecting women, with a growing incidence. To better understand the different behaviors associated with endometrial cancer, it is necessary to understand the changes that occur at a molecular level. CD133 is one of the factors that regulate tumor progression, which is primarily known as the transmembrane glycoprotein associated with tumor progression or cancer stem cells. The aim of our study was to assess the impact of subcellular CD133 expression on the clinical course of endometrial cancer. (2) Methods: CD133 expression in the plasma membrane, nucleus, and cytoplasm was assessed by immunohistochemical staining in a group of 64 patients with endometrial cancer representing FIGO I-IV stages, grades 1–3 and accounting for tumor angioinvasion. (3) Results: Nuclear localization of CD133 expression was increased in FIGO IB-IV stages compared to FIGO IA. Furthermore, CD133 expression in the nucleus and plasma membrane is positively and negatively associated with a higher grade of endometrial cancer and angioinvasion, respectively. (4) Conclusions: Our findings suggest that positive nuclear CD133 expression in the tumor may be related to a less favorable prognosis of endometrial carcinoma patients and has emerged as a useful biomarker of a high-risk group.

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