CLDN11 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Aliases | CLDN11 , OSP, OTM, claudin 11, HLD22 | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 601326 MGI: 106925 HomoloGene: 4093 GeneCards: CLDN11 | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Claudin-11 is a protein that in humans is encoded by the CLDN11 gene. [5] [6] [7] It belongs to the group of claudins and was the first member of the family to be knocked out in mice, thereby demonstrating the central role of claudins for intramembranous strands observed in freeze-fracture images. [8]
The protein encoded by this gene belongs to the claudin family of tight junction associated proteins and is a major component of central nervous system myelin that is necessary for normal CNS function, [9] hearing, [10] and spermatogenesis. [8] There is growing evidence that the protein determines the permeability between layers of myelin sheaths [11] and, with its expression highly regulated during development, may play an important role in cellular proliferation and migration. In addition, the protein is a candidate autoantigen in the development of autoimmune demyelinating disease. [7] Finally, experiments in Cldn11-null mice demonstrate that behavioral phenotypes in open field tests, as well as defects in sound lateralization, accompany changes in neurotransmitter levels in the amygdala/ventral hippocampus and auditory brainstem. This study reveals a molecular mechanism by which changes to myelin membrane properties in the absence of degenerative pathology, could lead to neuropsychiatric disease in humans. [12]
Wallerian degeneration is an active process of degeneration that results when a nerve fiber is cut or crushed and the part of the axon distal to the injury degenerates. A related process of dying back or retrograde degeneration known as 'Wallerian-like degeneration' occurs in many neurodegenerative diseases, especially those where axonal transport is impaired such as ALS and Alzheimer's disease. Primary culture studies suggest that a failure to deliver sufficient quantities of the essential axonal protein NMNAT2 is a key initiating event.
Myelin oligodendrocyte glycoprotein (MOG) is a glycoprotein believed to be important in the myelination of nerves in the central nervous system (CNS). In humans this protein is encoded by the MOG gene. It is speculated to serve as a necessary "adhesion molecule" to provide structural integrity to the myelin sheath and is known to develop late on the oligodendrocyte.
Occludin is a transmembrane protein that regulates the permeability of epithelial and endothelial barriers. It was first identified in epithelial cells as a 65 kDa integral plasma-membrane protein localized at the tight junctions. Together with Claudins, and zonula occludens-1 (ZO-1), occludin has been considered a staple of tight junctions, and although it was shown to regulate the formation, maintenance, and function of tight junctions, its precise mechanism of action remained elusive and most of its actions were initially attributed to conformational changes following selective phosphorylation, and its redox-sensitive dimerization. However, mounting evidence demonstrated that occludin is not only present in epithelial/endothelial cells, but is also expressed in large quantities in cells that do not have tight junctions but have very active metabolism: pericytes, neurons and astrocytes, oligodendrocytes, dendritic cells, monocytes/macrophages lymphocytes, and myocardium. Recent work, using molecular modeling, supported by biochemical and live-cell experiments in human cells demonstrated that occludin is a NADH oxidase that influences critical aspects of cell metabolism like glucose uptake, ATP production and gene expression. Furthermore, manipulation of occludin content in human cells is capable of influencing the expression of glucose transporters, and the activation of transcription factors like NFkB, and histone deacetylases like sirtuins, which proved capable of diminishing HIV replication rates in infected human macrophages under laboratory conditions.
Remyelination is the process of propagating oligodendrocyte precursor cells to form oligodendrocytes to create new myelin sheaths on demyelinated axons in the CNS. This is a process naturally regulated in the body and tends to be very efficient in a healthy CNS. The process creates a thinner myelin sheath than normal, but it helps to protect the axon from further damage, from overall degeneration, and proves to increase conductance once again. The processes underlying remyelination are under investigation in the hope of finding treatments for demyelinating diseases, such as multiple sclerosis.
Myelin-associated glycoprotein is a type 1 transmembrane protein glycoprotein localized in periaxonal Schwann cell and oligodendrocyte membranes, where it plays a role in glial-axonal interactions. MAG is a member of the SIGLEC family of proteins and is a functional ligand of the NOGO-66 receptor, NgR. MAG is believed to be involved in myelination during nerve regeneration in the PNS and is vital for the long-term survival of the myelinated axons following myelinogenesis. In the CNS MAG is one of three main myelin-associated inhibitors of axonal regeneration after injury, making it an important protein for future research on neurogenesis in the CNS.
Proteolipid protein 1 (PLP1) is a form of myelin proteolipid protein (PLP). Mutations in PLP1 are associated with Pelizaeus–Merzbacher disease. It is a 4 transmembrane domain protein which is proposed to bind other copies of itself on the extracellular side of the membrane. In a myelin sheath, as the layers of myelin wraps come together, PLP will bind itself and tightly hold the cellular membranes together.
Gap junction beta-1 protein (GJB1), also known as connexin 32 (Cx32), is a transmembrane protein that in humans is encoded by the GJB1 gene. Gap junction beta-1 protein is a member of the gap junction connexin family of proteins that regulates and controls the transfer of communication signals across cell membranes, primarily in the liver and peripheral nervous system. However, the protein is expressed in multiple organs, including in oligodendrocytes in the central nervous system.
Claudin 4, also known as CLDN4, is a protein which in humans is encoded by the CLDN4 gene. It belongs to the group of claudins.
Claudin-6 is a protein that in humans is encoded by the CLDN6 gene. It belongs to the group of claudins. The knockout mice of mouse homolog exhibit no phenotype, indicating that claudin-6 is dispensable for normal development and homeostasis.
Claudin-2 is a protein that in humans is encoded by the CLDN2 gene. It belongs to the group of claudins.
Claudin-12 is a protein that in humans is encoded by the CLDN12 gene. It belongs to the group of claudins.
Claudin-8 is a protein that in humans is encoded by the CLDN8 gene. It belongs to the group of claudins.
Claudin-14 is a protein that in humans is encoded by the CLDN14 gene. It belongs to a related family of proteins called claudins.
Cingulin is a cytosolic protein encoded by the CGN gene in humans localized at tight junctions (TJs) of vertebrate epithelial and endothelial cells.
Claudin-17 is a protein that in humans is encoded by the CLDN17 gene. It belongs to the group of claudins; claudins are cell-cell junction proteins that keep that maintains cell- and tissue-barrier function. It forms anion-selective paracellular channels and is localized mainly in kidney proximal tubules.
Myelin transcription factor 1 is a protein that in humans is encoded by the MYT1 gene.
Claudin-10 is a protein that in humans is encoded by the CLDN10 gene. It belongs to the group of claudins.
Gap junction gamma-3, also known as connexin-29 (Cx29) or gap junction epsilon-1 (GJE1), is a protein that in humans is encoded by the GJC3 gene.
Myelin regulatory factor, also known as myelin gene regulatory factor (MRF), is a protein that in humans is encoded by the MYRF gene.
Tight junction proteins are molecules situated at the tight junctions of epithelial, endothelial and myelinated cells. This multiprotein junctional complex has a regulatory function in passage of ions, water and solutes through the paracellular pathway. It can also coordinate the motion of lipids and proteins between the apical and basolateral surfaces of the plasma membrane. Thereby tight junction conducts signaling molecules, that influence the differentiation, proliferation and polarity of cells. So tight junction plays a key role in maintenance of osmotic balance and trans-cellular transport of tissue specific molecules. Nowadays is known more than 40 different proteins, that are involved in these selective TJ channels.