Claudins
Claudin-3
Claudin-4
Tight Junctions
Claudin-1
Occludin
Claudin-5
Membrane Proteins
Zonula Occludens-2 Protein
Claudin-2
MARVEL Domain Containing 2 Protein
Zonula Occludens-1 Protein
Zonula Occludens Proteins
Clostridium perfringens
Permeability
Epithelial Cells
Loop of Henle
Dogs
Madin Darby Canine Kidney Cells
Cell Membrane Permeability
Junctional Adhesion Molecules
Keratosis, Actinic
Freeze Fracturing
Claudin-11/OSP-based tight junctions of myelin sheaths in brain and Sertoli cells in testis. (1/444)
Members of the newly identified claudin gene family constitute tight junction (TJ) strands, which play a pivotal role in compartmentalization in multicellular organisms. We identified oligodendrocyte-specific protein (OSP) as claudin-11, a new claudin family member, due to its sequence similarity to claudins as well as its ability to form TJ strands in transfected fibroblasts. Claudin-11/OSP mRNA was expressed in the brain and testis. Immunofluorescence microscopy with anti-claudin-11/OSP polyclonal antibody (pAb) and anti-neurofilament mAb revealed that in the brain claudin-11/OSP-positive linear structures run in a gentle spiral around neurofilament-positive axons. At the electron microscopic level, these linear structures were identified as the so-called interlamellar strands in myelin sheaths of oligodendrocytes. In testis, well-developed TJ strands of Sertoli cells were specifically labeled with anti-claudin-11/OSP pAb both at immunofluorescence and electron microscopic levels. These findings indicated that the interlamellar strands of oligodendrocyte myelin sheaths can be regarded as a variant of TJ strands found in many other epithelial cells, and that these strands share a specific claudin species, claudin-11/OSP, with those in Sertoli cells to create and maintain the repeated compartments around axons by oligodendrocytes. (+info)Transmembrane proteins in the tight junction barrier. (2/444)
Three types of transmembrane proteins have been identified within the tight junction, but it remains to be determined how they provide the molecular basis for regulating the paracellular permeability for water, solutes, and immune cells. Several of these proteins localize specifically within the continuous cell-to-cell contacts of the tight junction. One of these, occludin, is a cell adhesion molecule that has been demonstrated to influence ion and solute permeability. The claudins are a family of four-membrane spanning proteins; unexpectedly, other members of this family have already been characterized without recognizing their relationship to tight junctions. Junction adhesion molecule, the most recently identified tight junction component, is a member of the Ig superfamily and influences the paracellular transmigration of immune cells. A plaque of cytoplasmic proteins under the junction may be responsible for scaffolding the transmembrane proteins, creating a link to the perijunctional actin cytoskeleton and transducing regulatory signals that control the paracellular barrier. (+info)Paracellin-1, a renal tight junction protein required for paracellular Mg2+ resorption. (3/444)
Epithelia permit selective and regulated flux from apical to basolateral surfaces by transcellular passage through cells or paracellular flux between cells. Tight junctions constitute the barrier to paracellular conductance; however, little is known about the specific molecules that mediate paracellular permeabilities. Renal magnesium ion (Mg2+) resorption occurs predominantly through a paracellular conductance in the thick ascending limb of Henle (TAL). Here, positional cloning has identified a human gene, paracellin-1 (PCLN-1), mutations in which cause renal Mg2+ wasting. PCLN-1 is located in tight junctions of the TAL and is related to the claudin family of tight junction proteins. These findings provide insight into Mg2+ homeostasis, demonstrate the role of a tight junction protein in human disease, and identify an essential component of a selective paracellular conductance. (+info)Ca(2+)-independent cell-adhesion activity of claudins, a family of integral membrane proteins localized at tight junctions. (4/444)
In multicellular organisms, various compositionally distinct fluid compartments are established by epithelial and endothelial cellular sheets. For these cells to function as barriers, tight junctions (TJs) are considered to create a primary barrier for the diffusion of solutes through the paracellular pathway [1] [2] [3]. In ultrathin sections viewed under electron microscopy, TJs appear as a series of apparent fusions, involving the outer leaflets of plasma membranes of adjacent cells, to form the so-called kissing points of TJs, where the intercellular space is completely obliterated [4]. Claudins are a family of 16 proteins whose members have been identified as major integral membrane proteins localized exclusively at TJs [5] [6] [7] [8]. It remains unclear, however, whether claudins have the cell-adhesion activity that would explain the unusual intercellular adhesion at TJs. Using mouse L-fibroblast transfectants expressing various amounts of claudin-1, -2 or -3, we found that these claudins possess Ca(2+)-independent cell-adhesion activity. Using ultrathin-section electron microscopy, we observed many kissing points of TJs between adjacent transfectants. Furthermore, the cell-adhesion activity of occludin, another integral membrane protein localized at TJs [9] [10] [11], was negligible when compared with that of claudins. Thus, claudins are responsible for TJ-specific obliteration of the intercellular space. (+info)Endothelial claudin: claudin-5/TMVCF constitutes tight junction strands in endothelial cells. (5/444)
Tight junctions (TJs) in endothelial cells are thought to determine vascular permeability. Recently, claudin-1 to -15 were identified as major components of TJ strands. Among these, claudin-5 (also called transmembrane protein deleted in velo-cardio-facial syndrome [TMVCF]) was expressed ubiquitously, even in organs lacking epithelial tissues, suggesting the possible involvement of this claudin species in endothelial TJs. We then obtained a claudin-6-specific polyclonal antibody and a polyclonal antibody that recognized both claudin-5/TMVCF and claudin-6. In the brain and lung, immunofluorescence microscopy with these polyclonal antibodies showed that claudin-5/TMVCF was exclusively concentrated at cell-cell borders of endothelial cells of all segments of blood vessels, but not at those of epithelial cells. Immunoreplica electron microscopy revealed that claudin-5/TMVCF was a component of TJ strands. In contrast, in the kidney, the claudin-5/TMVCF signal was restricted to endothelial cells of arteries, but was undetectable in those of veins and capillaries. In addition, in all other tissues we examined, claudin-5/TMVCF was specifically detected in endothelial cells of some segments of blood vessels, but not in epithelial cells. Furthermore, when claudin-5/TMVCF cDNA was introduced into mouse L fibroblasts, TJ strands were reconstituted that resembled those in endothelial cells in vivo, i.e., the extracellular face-associated TJs. These findings indicated that claudin-5/TMVCF is an endothelial cell-specific component of TJ strands. (+info)Clostridium perfringens enterotoxin fragment removes specific claudins from tight junction strands: Evidence for direct involvement of claudins in tight junction barrier. (6/444)
Claudins, comprising a multigene family, constitute tight junction (TJ) strands. Clostridium perfringens enterotoxin (CPE), a single approximately 35-kD polypeptide, was reported to specifically bind to claudin-3/RVP1 and claudin-4/CPE-R at its COOH-terminal half. We examined the effects of the COOH-terminal half fragment of CPE (C-CPE) on TJs in L transfectants expressing claudin-1 to -4 (C1L to C4L, respectively), and in MDCK I cells expressing claudin-1 and -4. C-CPE bound to claudin-3 and -4 with high affinity, but not to claudin-1 or -2. In the presence of C-CPE, reconstituted TJ strands in C3L cells gradually disintegrated and disappeared from their cell surface. In MDCK I cells incubated with C-CPE, claudin-4 was selectively removed from TJs with its concomitant degradation. At 4 h after incubation with C-CPE, TJ strands were disintegrated, and the number of TJ strands and the complexity of their network were markedly decreased. In good agreement with the time course of these morphological changes, the TJ barrier (TER and paracellular flux) of MDCK I cells was downregulated by C-CPE in a dose-dependent manner. These findings provided evidence for the direct involvement of claudins in the barrier functions of TJs. (+info)Manner of interaction of heterogeneous claudin species within and between tight junction strands. (7/444)
In tight junctions (TJs), TJ strands are associated laterally with those of adjacent cells to form paired strands to eliminate the extracellular space. Claudin-1 and -2, integral membrane proteins of TJs, reconstitute paired TJ strands when transfected into L fibroblasts. Claudins comprise a multigene family and more than two distinct claudins are coexpressed in single cells, raising the questions of whether heterogeneous claudins form heteromeric TJ strands and whether claudins interact between each of the paired strands in a heterophilic manner. To answer these questions, we cotransfected two of claudin-1, -2, and -3 into L cells, and detected their coconcentration at cell-cell borders as elaborate networks. Immunoreplica EM confirmed that distinct claudins were coincorporated into individual TJ strands. Next, two L transfectants singly expressing claudin-1, -2, or -3 were cocultured and we found that claudin-3 strands laterally associated with claudin-1 and -2 strands to form paired strands, whereas claudin-1 strands did not interact with claudin-2 strands. We concluded that distinct species of claudins can interact within and between TJ strands, except in some combinations. This mode of assembly of claudins could increase the diversity of the structure and functions of TJ strands. (+info)Direct binding of three tight junction-associated MAGUKs, ZO-1, ZO-2, and ZO-3, with the COOH termini of claudins. (8/444)
ZO-1, ZO-2, and ZO-3, which contain three PDZ domains (PDZ1 to -3), are concentrated at tight junctions (TJs) in epithelial cells. TJ strands are mainly composed of two distinct types of four-transmembrane proteins, occludin, and claudins, between which occludin was reported to directly bind to ZO-1/ZO-2/ZO-3. However, in occludin-deficient intestinal epithelial cells, ZO-1/ZO-2/ZO-3 were still recruited to TJs. We then examined the possible interactions between ZO-1/ZO-2/ZO-3 and claudins. ZO-1, ZO-2, and ZO-3 bound to the COOH-terminal YV sequence of claudin-1 to -8 through their PDZ1 domains in vitro. Then, claudin-1 or -2 was transfected into L fibroblasts, which express ZO-1 but not ZO-2 or ZO-3. Claudin-1 and -2 were concentrated at cell-cell borders in an elaborate network pattern, to which endogenous ZO-1 was recruited. When ZO-2 or ZO-3 were further transfected, both were recruited to the claudin-based networks together with endogenous ZO-1. Detailed analyses showed that ZO-2 and ZO-3 are recruited to the claudin-based networks through PDZ2 (ZO-2 or ZO-3)/PDZ2 (endogenous ZO-1) and PDZ1 (ZO-2 or ZO-3)/COOH-terminal YV (claudins) interactions. In good agreement, PDZ1 and PDZ2 domains of ZO-1/ZO-2/ZO-3 were also recruited to claudin-based TJs, when introduced into cultured epithelial cells. The possible molecular architecture of TJ plaque structures is discussed. (+info)Keratosis, actinic can occur on any sun-exposed area of the body, but it is most common on the face, ears, neck, hands, and arms. It typically develops in people who have fair skin, light hair, and light eyes, as well as those who spend a lot of time outdoors or live in sunny climates.
The symptoms of keratosis, actinic can vary depending on the severity of the condition, but may include:
* Scaly, rough, or crusty patches on the skin
* Redness, itching, or burning sensations on the affected areas
* Thickening and darkening of the skin in advanced cases
* Open sores or ulcers in severe cases
Keratosis, actinic can be diagnosed through a physical examination of the skin and may involve a biopsy to rule out other conditions. Treatment typically involves measures to protect the skin from further sun exposure, such as using sunscreen, wearing protective clothing, and seeking shade when the sun is strongest. In some cases, topical creams or ointments may be prescribed to help reduce inflammation and promote healing.
Prevention is key in avoiding keratosis, actinic, as it can be a chronic condition that can worsen over time if left untreated. Protecting the skin from sun exposure and seeking medical attention if symptoms persist or worsen can help prevent complications and improve quality of life for those affected by this condition.
CLDN1
Tight junction proteins
CLDN12
CLDN20
CLDN4
CLDN17
CLDN5
CLDN7
CLDN9
CLDN8
CLDN22
CLDN10
CLDN18
CLDN19
CLDN15
CLDN6
CLDN16
CLDN2
Intestinal epithelium
Claudin
Intestinal permeability
Magnesium transporter
CLDN14
Claudin 25
Paracellular transport
Uterine epithelium
Junctional adhesion molecule
Tight junction
MPDZ
Septate junction
Interviews Archives - Claudins
Microbial metabolite from berries and pomegranates may help address bowel disease- Technology News, Firstpost
Microarrays | Free Full-Text | Improving Pathological Assessment of Breast Cancer by Employing Array-Based Transcriptome...
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Claudin18.2 is a novel molecular biomarker for tumor-targeted immunotherapy | Biomarker Research | Full Text
TRPM6 and hypomagnesaemia/hypocalcaemia<...
Bioengineering the Blood‐gas Barrier - Comprehensive Physiology
Host responses to Clostridium perfringens challenge in a chicken model of chronic stress | Gut Pathogens | Full Text
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Isomaltose | Harvard Catalyst Profiles | Harvard Catalyst
Human CLDN18(Claudin 18) ELISA Kit - The International Society for Microbiology
anti-Homo sapiens (Human) CLDN18 Antibody raised in Rabbit - Cusabio
4.6 Connections between Cells and Cellular Activities - Biology for AP® Courses | OpenStax
March | 2014 | PKC Pathway
Getting To Know Cancer Home Page
Ankyrin Receptors
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β1 Integrin regulates adult lung alveolar epithelial cell inflammation
The Diagnostic Role of Claudins in Serous Effusions
Claudins in barrier and transport function-the kidney - PubMed
Hypomagnesemia: Practice Essentials, Pathophysiology, Etiology
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Interaction between Epithelial Sodium Channel γ-Subunit and Claudin-8 Modulates Paracellular Sodium Permeability in Renal...
Prenatal Exposure to Per- and Polyfluoroalkyl Substances, Umbilical Cord Blood DNA Methylation, and Cardio-Metabolic Indicators...
CLDN8
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The First Line of Defense: The Effects of Alcohol on Post-Burn Intestinal Barrier, Immune Cells, and Microbiome | Alcohol...
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Expression of claudins2
- Unfortunately, subclone #45 did not form enterocyte-like cell monolayers due to low expression of claudins and β -actin. (aspetjournals.org)
- Evaluated expression of claudins in gastric cancer and determined their significance for patient outcome. (cusabio.com)
Proteins5
- 9. Claudins and other tight junction proteins. (nih.gov)
- The cells remain together with the help of certain proteins like claudins and zona occludin-1. (firstpost.com)
- Claudins are integral membrane proteins and components of tight junction strands. (nih.gov)
- Claudins (CLDNs) are a family of proteins and are important components of tight junctions (TJs) [ 1 ], which form a paracellular barrier to control the flow of molecules between cells. (biomedcentral.com)
- Our group also demonstrated that claudins, the key family of tight-junction sealing proteins, create charge- and size-selective pores through the tight junction to allow tissue-specific ion permeability. (nih.gov)
Data1
- Our current data suggest that claudins may be important for cell motility and invasion. (nih.gov)
Barrier2
- [ 8 ] Recent studies have shown that the barrier function of claudins can be modulated also through phosphorylation of the serine and/or threonine phosphorylation sites at the carboxy tail by various kinases such as WNK4 [ 9 ] and cyclic adenosine monophosphate dependent protein kinase. (medscape.com)
- DE caused upregulation (3 to 5-fold) of mRNA transcripts for matrix metalloproteinase 9 (Mmp9), claudins (Cldn1 and Cldn2), and Gfap (1.6-fold) in the OB, suggestive of altered blood-brain barrier integrity and reactive gliosis. (cdc.gov)
Cancers1
- Since our initial findings, other research groups have found that claudins are dysregulated in many other cancers. (nih.gov)
Tight junction2
- Claudins are a family of tight junction (TJ)-specific integral membrane proteins, including more than 20 members to date. (medscape.com)
- Claudins are integral membrane proteins and components of tight junction strands. (nih.gov)
Findings1
- Although the function of claudins in cancer cells is not clear, recent findings suggest their involvement in cancer cell survival [ 16 ] and invasion [ 20 ] mechanisms. (medscape.com)
Cell1
- The expression pattern of claudins varies considerably among cell types and tissues. (medscape.com)
Date1
- The role of claudins in the differential diagnosis of serosal tumors is limited to 1 study to date. (medscape.com)