Marker Protein In Cell Membrane

Membrane Marker

The membrane markers that undergo clustering and redistribution in response to VacA are the aforementioned every bit those that localize to the vacuole membrane in vacuolated cells, and experiments bespeak that there is a structural relationship between VacA-induced perinuclear clusters and VacA-induced vacuoles (Li et al., 2004b).

From: The Comprehensive Sourcebook of Bacterial Protein Toxins (Third Edition) , 2006

Definition and Nomenclature of Stem Cells

Nicole Arrighi , in Stem Cells, 2018

1.ii.vii Skin stem cells

The peel is the largest organ of the homo torso, and information technology protects against external aggressions, infections and aridity and provides thermoregulation and sensory perception. The skin consists of two tissues: there is the epidermis, a stratified, not-vascularized external epithelium, which is located above the dermis, a connective tissue composed mainly of dense fibrous compounds produced by fibroblasts. The epidermis is composed of two distinct layers: a locus of progressive differentiation of the keratinocytes migrating from the basal layer to the stratum corneum and the outermost layer. The epidermis and the hair follicle regenerate thank you to the SCs, which are quiescent and undifferentiated and ensure the maintenance of homeostasis and tissue regeneration. Several populations of SCs exist in the skin. These populations include the epidermal SCs, dermal mesenchymal SCs, hair follicle SCs, endothelial and hematopoietic SCs also as cells derived from the neural crest, such as the melanocytes.

The epidermis is the outermost layer of the human skin. It forms a protective, water-resistant envelope equanimous of a stratified squamous epithelium that rests on a basal lamina. The epidermis contains four cell types, namely keratinocytes, melanocytes, Langerhans cells and Merkel cells. Keratinocytes, which produce keratin, are the predominant cells of the epidermis. In the deepest office of the epidermis, called the basal layer, are the immature keratinocytes, at the proliferative stage, responsible for keratinopoiesis and renewal of the epidermis, which lasts 3–5 weeks. The classical model explaining the maintenance of peel homeostasis proposes that the SCs of the basal lamina separate more slowly than daughter cells, called transit amplifying cells. After several divisions, they differentiate and transit to the upper layers. The dermis houses several functional compounds of the peel, including the vascular and lymphatic systems and epidermal appendages (hair follicles, sebaceous glands and sweat glands).

Epidermal SCs are characterized by the expression of cytokeratins KRT15 and KRT19, α6 integrin and the absenteeism of transferrin CD71 receptor.

The hair follicle is a mini-organ of the skin that contains SCs from various developmental origins with various differentiation potentials. Information technology represents a niche of multipotent epithelial SCs. Several markers have been explored in mice, just only a few are confirmed in humans. The markers CD200, KRT15 and KRT19 are positive, whereas the cells do not express CD34, NES or LHX2. More mostly, these SCs have a profile of surface markers close to mesenchymal SCs that are positive for markers CD90, CD44, CD49b, CD105 and CD73 and differentiate into os, fatty tissue, cartilage or smooth musculus. SCs of the hair follicle are activated by various aggressions and migrate toward the epidermis to participate in its regeneration. They are involved in the homeostasis of the sebaceous gland. In addition, the hair follicle contains melanocyte SCs, which are responsible for the regeneration of melanocytes, a type of paint cell. Melanocytes produce melanin and therefore play a vital office in the pigmentation of skin and follicles.

From the dermis, pare-derived precursors (SKP) take been identified. They share certain characteristics with embryonic SCs of the neural crest. Multipotent, they are capable of producing in vitro a progeny of cells that are both neural and mesodermal. They have dissimilar properties from the other skin precursors. Transplanted in an adult mouse, these SKPs accept a morphology similar to that of endogenous fibroblasts; they express the fibroblast markers of the dermis: PDGFRα, blazon-I collagen, vimentin, fibronectin and fibroblast-specific antigens. In vivo, SKPs are recruited almost the fibrotic lesion and differentiate into myofibroblasts in the presence of serum.

Although universal membrane markers of the SCs of the dermis are sought, no specific marker has yet been identified. On the contrary, the SCs and the progenitors of the human dermis (dermal stalk/progenitor cells, hDSPCs) present three specific intracellular markers:

–: SOX2, the transcription factor, SRY, plays an essential role in maintaining the stalk nature of embryonic SCs and sure adult SCs, as in the dermal papillae, which are small protuberances of the dermis, which plunge into the epidermis, leading the oxygen and nutrients to the inner layers of epidermal cells.
–: NANOG, another marker of embryonic SCs, is besides expressed in the SC populations of the dermis and bone marrow.
–: S100B, the intracytosolic calcium-binding protein is overexpressed in the SCs of the peel.

Shim et al. demonstrated that the SC population and progenitors of the man dermis can be enriched by its power to adhere to type-IV collagen [SHI 13]. They can differentiate into mesoderm cells such as adipocytes, osteoblasts, chondrocytes and ectodermal progeny, such as neuronal cells. Three-dimensional suspended cultures have shown an increment in the expression of the three specific markers, compared to a two-dimensional civilisation.

This panorama of developed SCs shows that there are as many types of SCs specific to a tissue as organs. Avant-garde in specialization, these progenitors are localized in a tissue and establish its jail cell regeneration reservoir. At this stage of differentiation, the tissue-specific SCs cannot regenerate a different tissue than the i where they are located. To do so, it would be necessary to reprogram them and return to the original state they had in the embryo, where all directions were possible. Embryonic SCs nowadays absolute pluripotency described in the following section.

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Immunotoxicology Testing In Vitro

CLIVE MEREDITH , KLARA MILLER , in In Vitro Methods in Pharmaceutical Inquiry, 1997

A Dendritic cells

Dendritic cells lack most conventional surface membrane markers associated with the macrophage lineage, but expression of MHC class II is very strong and hence they are ofttimes called 'professional' antigen-presenting cells (APCs). They are found in lymphoid tissues and in the interstitial epithelium of the lung and other non-lymphoid organs. Langerhans' cells, which as well belong to the dendritic family, ⁷ are found in the epidermis of the skin. Activated dendritic cells are idea to be the almost constructive APCs considering they are able to present the appropriate antigenic peptides in the context of constitutively expressed co-stimulatory signals, ⁸ migrating to lymph nodes later taking up antigen in the periphery. In the lung the APC must exist capable of efficiently sampling extracellular fluids within the airway and of directed migration to paracortical zones in the regional lymph nodes, and information technology must be highly efficient in activating naive T cells. As notwithstanding, it is not clear which cytokine plays the more important role in activation, maturation and/or migration of dendritic cells; granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor (TNF) α and interleukin (IL) 1 have been implicated, and a recent written report has suggested that IL-4 may play an important role. ⁹ Coordinating to epidermal Langerhans' cells, airway and lung dendritic cells are restricted to antigen acquisition and processing in situ and only develop the chapters to nowadays antigen to T cells later on maturation and migration to the paracortical expanse of secondary lymphoid organs. ^ten

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Biochemistry and Molecular Biology

Due west.R. Terra , C. Ferreira , in Comprehensive Molecular Insect Science, 2005

4.five.half-dozen.4 Phosphatases

Alkali metal phosphatase is usually a midgut microvillar membrane marking in dipteran and lepidopteran species, although it may also occur in midgut basolateral membranes and even as a secretory enzyme. Acid phosphatase is normally soluble in the cytosol of midgut cells in many insects and may also appear in midgut contents or be constitute membrane-spring in midgut cells ( Terra and Ferreira, 1994).

The best-known alkali metal phosphatases are those from B. mori (Lepidoptera: Bombycidae) larval midgut. The major membrane-leap and the small-scale soluble alkaline phosphatases were purified and shown to be monomeric enzymes with the post-obit properties: (1) soluble enzyme, molecular mass of 61 kDa, pH optimum 9.8; (ii) membrane-bound enzyme, molecular mass of 58 kDa, pH optimum ten.9. Both enzymes take wide substrate specificity and are inhibited by cysteine. The membrane-bound alkaline phosphatase occurs in the microvillar membranes of columnar cells, whereas the soluble enzyme is loosely fastened to the goblet cell apical membrane facing the cell cavity (Eguchi, 1995). The determination of the complete sequence of the membrane-bound alkaline phosphatase led to the finding of putative regions for phosphatidylinositol anchoring, zinc-binding site merely not for Northward-glycosylation, despite the fact that the enzyme contains Northward-linked oligosaccharides (Itoh et al., 1991). The sequence of the soluble alkaline phosphatase was also adamant and has high identity with the membrane-bound enzyme (Itoh et al., 1999).

Acrid phosphatases have been characterized in some item but in Rhodnius prolixus (Hemiptera: Reduvidae). The major enzyme activity is soluble and has the following backdrop: wide specificity, a molecular mass of 82 kDa, Km for p-nitrophenyl phosphate 0.seven mM, and is inhibited by fluoride, tartrate, and molybdate. The minor enzyme activity is membrane-jump and is resolved into two enzymes (123 and 164 kDa) which are resistant to fluoride and tartrate (Terra et al., 1988).

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Autophagy in Fungi and Mammals

Daniel J. Klionsky , Ju Guan , in Encyclopedia of Biological Chemistry, 2004

A Novel Organelle for De Novo Vesicle Formation

In vivo fluorescence microscopy studies take colocalized the autophagosomal membrane marking protein Atg8 with several other Atg proteins on a perivacuolar structure. This structure is physiologically functional and appears to play a pivotal function in autophagosome germination; therefore, it has been termed the pre-autophagosomal construction (PAS). Localized on the PAS are two conjugates: Atg12, covalently linked to Atg5, and Atg8, covalently attached to phosphatidylethanolamine (Atg8-PE). These conjugates may directly participate in the generation of autophagosomes. Formation of the Atg12-Atg5 and Atg8-PE conjugates involves ubiquitin-like cascades. Recruitment of Atg12-Atg5 and Atg8 to the PAS depends on the function of the transmembrane protein Atg9 and an autophagy-specific phosphatidylinositol iii-kinase circuitous, underlying the key part of specific lipids in autophagosome formation.

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Prison cell Death | Autophagy in Fungi and Mammals☆

Jiefei Geng , ... Sarah C. Stainbrook , in Encyclopedia of Biological Chemistry (Third Edition), 2021

Phagophore assembly site and de novo vesicle formation

In vivo fluorescence microscopy studies have colocalized the autophagosomal membrane marker protein Atg8 with several other Atg proteins at a perivacuolar site. This site is physiologically functional and plays a pivotal office in autophagosome formation; therefore, it has been termed the phagophore assembly site (PAS). Localized on the PAS are ii conjugates, Atg12 covalently linked to Atg5, and Atg8 covalently attached to phosphatidylethanolamine (Atg8–PE). These conjugates are both essential in the generation of autophagosomes and Cvt vesicles. Germination of the Atg12–Atg5 and Atg8–PE conjugates involves ubiquitin-like cascades. Recruitment of Atg12–Atg5 and Atg8 to the PAS depends on the function of the transmembrane protein Atg9 and the autophagy-specific PtdIns3K complex (there are two PtdIns3K complexes in yeast), underlying the key role of specific lipids in autophagosome germination. Atg9 cycles between the PAS and multiple peripheral sites, which may correspond the donor membranes source(due south) that permit expansion of the phagophore.

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Computational Methods in Cell Biology

Alexandre Cunha , ... Elliot Grand. Meyerowitz , in Methods in Cell Biology, 2012

2 Method 2: Static imaging of living sepals for quantitative image assay

a.: Use a transgenic plant expressing a fluorescent plasma membrane mark, such every bit ATML1p::mCitrine-RCI2A. The found should be salubrious and actively flowering.
b.: Under a dissecting telescopic at nearly 32× times magnification, gently open up the flower using fine forceps (Dumont #v). Utilize a 23-gauge, 1-inch needle to cutting downward along the inner side of the sepal to remove the base of operations of the sepal from the blossom.
c.: Wet the sepal by placing information technology in 50 μl of 0.01% triton X-100 on a precleaned Aureate Seal microslide (Cat No 3010). Cover with an 18 mm foursquare cover skid (Corning True cat. No. 2865-18). Tap the side of the slide to displace air bubbles from the sepal. Remove the cover sideslip.
d.: Mount the sepal by placing it on a new slide in fresh 0.01% triton Ten-100. Carefully turn the sepal such that desired side faces up for imaging. In this case, the outer abaxial side was imaged. Note that unlike brands of slide have dissimilar properties that brand orientation of the sepal easier or more hard. Again carefully lower a cover sideslip over the sepal and tap the slide to remove air bubbles. For mosaic images, removing backlog mounting solution by placing the corner of a Kimwipe against the edge of the cover sideslip is essential. Otherwise, the sepal flattens as the liquid evaporates causing shifts between parts of the mosaic.
e.: Examine the sepal with epifluorescence on the confocal microscope to ensure that it is properly mounted, is not obscured past air bubbles, and was non damaged in the dissecting process.
f.: Set the lite path of the microscope such that the proper excitation is used and the proper emission is captured. Make sure to exclude chlorophyll (>635 nm). We used a Zeiss 510 Meta upright confocal microscope. For mCitrine, 514 excitation was used together with a dichroic mirror reflecting only lite less than 545 nm and a 530–600 nm ring pass filter, such that just 530–545 nm wavelength light reached the photomultiplier tube (PMT).
one thousand.: Optimize the brightness of the signal and decrease the background dissonance equally much equally possible through adjusting the laser output, manual, pinhole, detector proceeds, and amplifier commencement. For segmentation, compromising signal to achieve less noise is often better than increasing betoken with more racket. In our example, laser output = 50%, transmission = 28.1%, pinhole = 100 μm, detector gain = 711, amplifier offset = 0, and amplifier gain = i.
h.: Take multiple confocal stacks such that adjacent images tile (cover) the whole sepal with some overlap betwixt images. The mature sepal is larger than the field of view with either the 10× or 20×. Two images can be used at 10×, whereas six are more often than not required at xx×. The increased resolution at 20× is important for subsequent image processing.
i.: To create a complete epitome, make projections of each stack using the confocal software. Use Adobe Photoshop Photomerge function to make a single consummate paradigm. There are often slight alignment problems at the junctions between images. Carefully crop abroad groundwork that will interfere with automated sectionalisation. The image is now ready for segmentation.

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The immunology of inflammatory demyelinating disease

Hartmut Wekerle , Hans Lassmann , in McAlpine'due south Multiple Sclerosis (Fourth Edition), 2006

Gene expression during T-cell maturation

The developmental steps of T-cell differentiation take been defined by examining membrane markers and receptor-gene expression in thymic T-prison cell subsets during fetal development, afterwards regeneration, and in transgenic animals. Obviously, productive rearrangement of the genes encoding T-cell receptor α and β chains is the first cardinal event. Moreover, the progression of T-cell receptor expression is closely related to induction and surface expression of the ancillary molecules CD4 and CD8 on differentiating T lymphocytes.

At that place is consensus that T-cell progenitors migrating from the os marrow to the thymus take neither rearranged T-cell receptors nor CD4 or CD8 on their membranes. At this phase, the T-cell receptor genes are nonetheless located in germline germination at private loci on the chromosome. The T-cell receptor β-chain genes are rearranged first. They appear on the cell membrane together with a archaic surrogate α concatenation. This signals several differentiation steps – induction of both CD4 and CD8, and subsequent rearrangement of the α-concatenation genes. The CD4⁺ and CD8⁺ T-prison cell receptor-expressing thymocytes are at present ready to undergo selection events that result in the intact, functional T-prison cell repertoire composed of CD4⁺ and CD8⁺ single positive lymphocytes (Robey et al 1994).

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Plasma membrane properties and receptors in white adipose tissue

Max Lafontan , Michel Berlan , in New Perspectives in Adipose Tissue, 1985

7.ii.3.6 Miscellaneous enzymes and transport systems of fatty jail cell plasma membrane

Amidst the enzymes, 5′-nucleotidase, the well-known plasma membrane marker, has been studied in rat fatty cells ( Newby et al., 1975). This enzyme faces out of the prison cell, is a phosphohydrolase specific for 5′-nucleotides and is non subject field to hormonal regulation.

Guanylate cyclase action has been reported in rat fatty cells. This enzyme catalyses the transformation of GTP to cyclic GMP and PP_i. Although it seems that circadian GMP is not an important regulator of adipose tissue function, rat adipocyte plasma membrane exhibits high activity which is strongly enhanced by preincubation with a mild non-ionic detergent (Levilliers et al., 1978). Guanylate cyclase activity in detergent-dispersed plasma membranes from rat or man is highly sensitive to the nature of the substrate and to divalent cation concentrations, e.thou. low concentrations of Ca²⁺ (Levilliers et al., 1978; Lecot et al., 1981). This effect of Ca²⁺ on solubilized guanylate cyclase is the merely link with potential physiological function which can be proposed. Thus Ca²⁺ may act equally an intermediate in a putative hormonal control of the enzyme in the adipose tissue.

2 GTP-hydrolysing enzymes (GTPases), with different M _m values, have been demonstrated in hamster fat jail cell membranes (Aktories et al., 1982a). Factors known to inhibit adenylate cyclase (prostaglandin E₁, nicotinic acid, adenosine) were found to stimulate the low-Chiliad _m GTPase while existence ineffective on the high-One thousand _thousand GTPase action. The depression-K _m GTPase is probably involved in the regulation of the processes responsible for hormone-induced adenylate cyclase inhibition.

A nucleotide pyrophosphatase hydrolysing externally applied ATP has been described recently in rat fat cells (Mardh and Vega, 1980). The physiological relevance of this enzyme is still unclear although its connection with a mechanism for the regulation of permeability has been proposed.

Techniques of subcellular fractionation take also permitted the identification of fatty prison cell lipases every bit membrane-bound enzymes. A monoacylglycerol lipase firmly anchored in the plasma membrane has been divers in rat fat cells (Arnaud et al., 1979; Sakurada and Noma, 1981). Its physiological substrate, monoacylglycerol, may be a product of triacylglycerol hydrolysed in the capillaries. Moreover, a loosely bound triester lipase, which possesses the properties characteristic of lipoprotein lipase (LPL), has been found with the fatty cell membrane and could be the form of the enzyme that is secreted by the fat jail cell and moves to its site in the capillary. This observation fits with the possibility of activeness of multiple subcellular forms of LPL (Vanhove et al., 1978).

Studies conducted on rat fatty cells have permitted the identification of a membrane component which is involved in the ship of adenosine out of the adipocyte. The process was identified by the photoaffinity labelling of the components involved using a photoreactive derivative of adenosine, two-[³H]-8-azidoadenosine (Rosenblit and Levy, 1977, 1980). The derivative is transported past the same arrangement every bit adenosine and its photolysis promotes the covalent incorporation of the photoprobe into a 56 000-M _r glycoprotein of the plasma membrane. This glycoprotein is thought therefore to be a component of the transmembrane circuitous involved in adenosine transport.

The permeation of long-chain fatty acids into the adipocyte, recently studied by Abumrad et al. (1981), likewise seems to involve a specialized transport system. At physiological levels of unbound fatty acids, permeation of [¹⁴C]-oleate into isolated rat fat cells is facilitated by a saturable, phloretin-inhibitable mechanism which presumably involves a specific protein. Such a result indicates that a saturable carrier mechanism may facilitate the entry of fatty acids into adipocytes and could business relationship for all the permeation of unbound fatty acids at physiological concentrations.

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Constitute Cell Biological science

Xi He , ... Lilan Hong , in Methods in Jail cell Biological science, 2020

2.two.2 Expressing fluorescent poly peptide tags for sepal visualization

In add-on to directly staining before ascertainment, genetically expressing fluorescent proteins fused to plasma membrane markers such as RCI2A and Lti6b ( Hervieux et al., 2016; Roeder et al., 2010) is also a ordinarily used method to visualize plant jail cell outlines. This approach allows alive imaging of developing sepals. A multifariousness of common fluorescent proteins (e.g., GFP, Venus, mYFP, mCitrine, mCherry) have been used for this purpose (Heisler et al., 2005; Hervieux et al., 2016; Roeder et al., 2010).

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Book 2

Yong Zhou , Victor J. Thannickal , in Encyclopedia of Tissue Technology and Regenerative Medicine, 2019

Extracellular Vesicles every bit Messengers in the MSC-Microenvironment Interaction

Extracellular vesicles (EVs) are small-scale membrane vesicles. Distinguished by size, origin, and specific membrane markers, EVs are classified into exosomes (40–150 nm), microvesicles (0.1–ii μm), and apoptotic bodies (1–4 μm) (Lötvall et al., 2014). A growing torso of data suggest that MSCs transfer/secrete unlike populations of EVs containing DNA, RNA (mRNA, microRNA, and noncoding RNA), protein, lipids, and organelles such equally mitochondria to other cells and the microenvironment (Lee et al., 2012; Ragni et al., 2017; Islam et al., 2012). Utilizing EVs, important point molecules tin exist delivered from MSCs to multiple cells and locations, modifying the target cell'due south gene expression, signaling, and overall role (Barrès et al., 2010; Tian et al., 2010; Skog et al., 2008).

Many studies accept focused on the interaction of MSC-derived exosomes with the immune system, including dendritic cell maturation and Treg and B cell responses (Théry et al., 2009; Kitazawa et al., 2012; Budoni et al., 2013). Results from these studies suggest that MSC-derived exosomes are, in general, immunosuppressive (Robbins and Morelli, 2014; Mokarizadeh et al., 2012). Proteomic analysis of the MSC secretome detected that many immunomodulators, including CD63, CD81, moesin, Alix, TSG101, and heat shock protein 70 (HSP70) were enriched in exosomes (Kourembanas, 2015). MSC-derived EVs promote immunotolerant signaling past increasing T regulatory cells, upregulation of immunosuppressive cytokine IL-10, and induction of effector T cell apoptosis (Mokarizadeh et al., 2012; Del Fattore et al., 2015). In a hypoxia-induced PH model, administration of MSC-derived exosomes protected against the top of right ventricular systolic force per unit area and the development of RVH, while CM depleted of EVs had no such protective effects (Lee et al., 2012). Additionally, exosome treatment abrogates early on hypoxic macrophage influx and downregulates hypoxia-activated inflammatory pathways (Lee et al., 2012).

Specific miRNAs in MSC-EVs have emerged as mediators of the protective furnishings of MSC administration in several preclinical lung disease models (Cruz et al., 2015; Abreu et al., 2016). For instance, administration of MSC-derived exosomes upregulated the miRNA-17 superfamily of micro-RNA clusters in a murine model of PH (Lee et al., 2012). In this model, MSC-derived exosomes also increased lung levels of miRNA-204. It has bee shown that MSC-EV-mediated transfer of microRNAs to human monocytes restored intracellular ATP, reduced levels of proinflammatory mediators, and increased the phagocytic properties of LPS-primed man monocytes (Matthay, 2017).

It has been institute that MSCs tin can transfer mitochondrial Dna to other cells, restoring mitochondrial function of the recipient cells (Spees et al., 2006). In LPS-treated mouse lungs, the transfer of MSC mitochondria, and maybe other cytosolic components, through connexin bridges increases alveolar ATP concentrations, inhibits surfactant secretion, and protects against alveolar leukocytosis and protein leak (Islam et al., 2012). MSC-derived exosomes stimulate expansion, proliferation, and differentiation of endogenous distal lung airway progenitor cells, suggesting that exosomes promote cellular repair and replacement of injured cells (Tropea et al., 2012). Additionally, MSC-derived EVs have been implicated in the tissue-restoring furnishings of MSCs, including antioxidant, antitumor effects and microbicidal activities (Alcayaga-Miranda et al., 2016, 2017).

In summary, EVs released from MSCs showroom immunosuppressive and antiinflammatory properties, subtract oxidative stress, increase ATP, and promote bacterial clearance. Specific EV components responsible for these actions remain to exist determined and likely vary depending on the lung injury model (Abreu et al., 2016).

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