|, ZO-1, Tight junction protein 1|
Zonula occludens-1 ZO-1, also known as Tight junction protein-1 is a 220-kD peripheral membrane protein that is encoded by the TJP1 gene in humans.It belongs to the family of zona occludens proteins (ZO-1, ZO-2, and ZO-3), which are tight junction-associated proteins and of which, ZO-1 is the first to be cloned. It was first isolated in 1986 by Stevenson and Goodenough using a monoclonal antibody raised in rodent liver to recognise a 225-kD polypeptide in whole liver homogenates and in tight junction-enriched membrane fractions. It has a role as a scaffold protein which cross-links and anchors Tight Junction (TJ) strand proteins, which are fibril-like structures within the lipid bilayer, to the actin cytoskeleton.
This gene encodes a protein located on a cytoplasmic membrane surface of intercellular tight junctions. The encoded protein may be involved in signal transduction at cell–cell junctions. Two transcript variants encoding distinct isoforms have been identified for this gene.
Tight junction protein 1 has been shown to interact with:
Tight junctions, also known as occluding junctions or zonulae occludentes are multiprotein junctional complexes whose general function is to prevent leakage of transported solutes and water and seals the paracellular pathway. Tight junctions may also serve as leaky pathways by forming selective channels for small cations, anions, or water. Tight junctions are present mostly in vertebrates. The corresponding junctions that occur in invertebrates are septate junctions.
Catenin beta-1, also known as β-catenin, is a protein that in humans is encoded by the CTNNB1 gene.
Occludin is an enzyme that oxidizes NADH. It was first identified in epithelial cells as a 65 kDa integral plasma-membrane protein localized at the tight junctions, and together with Claudins, and zonula occludens-1 (ZO-1), has been considered a staple of tight junctions. Although it was originally 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 its selective phosphorylation., and its redox-sensitive dimerization However, mounting evidence demonstrated that occludin is not only present in epithelial/endothelial cells, but is also found in large amounts 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 histones like sirtuins, which in a laboratory setting, proved capable of diminishing HIV replication rates in infected human macrophages.
Alpha-catenin was proposed to function as a linking protein between cadherins and actin-containing filaments of the cytoskeleton. It has been reported that the actin binding proteins vinculin and alpha-actinin can bind to alpha-catenin. However, a protein complex including a cadherin, actin, beta-catenin and alpha-catenin has not been isolated. It has been suggested that alpha-catenin does not bind with high affinity to both actin filaments and the E-cadherin-beta-catenin complex at the same time. It has been observed that when alpha-catenin is not in a molecular complex with beta-catenin, it dimerizes and functions to regulate actin filament assembly, possibly by competing with Arp2/3 protein. Alpha catenin exhibits significant protein dynamics.
Afadin is a protein that in humans is encoded by the AFDN gene.
Claudin-1 is a protein that in humans is encoded by the CLDN1 gene. It belongs to the group of claudins.
Tight junction protein ZO-2 is a protein that in humans is encoded by the TJP2 gene.
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.
Catenin delta-1 is a protein that in humans is encoded by the CTNND1 gene.
Junctional adhesion molecule A is a protein that in humans is encoded by the F11R gene. It has also been designated as CD321.
Radixin is a protein that in humans is encoded by the RDX gene.
Claudin 3, also known as CLDN3, is a protein which in humans is encoded by the CLDN3 gene. It is a member of the claudin protein family.
Claudin-7 is a protein that in humans is encoded by the CLDN7 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.
Claudin-2 is a protein that in humans is encoded by the CLDN2 gene. It belongs to the group of claudins.
Cingulin is a cytosolic protein encoded by the CGN gene in humans localized at tight junctions (TJs) of vertebrate epithelial and endothelial cells.
Stress fibers are contractile actin bundles found in non-muscle cells. They are composed of actin (microfilaments) and non-muscle myosin II (NMMII), and also contain various crosslinking proteins, such as α-actinin, to form a highly regulated actomyosin structure within non-muscle cells. Stress fibers have been shown to play an important role in cellular contractility, providing force for a number of functions such as cell adhesion, migration and morphogenesis.
αE-catenin, also known as Catenin alpha-1 is a protein that in humans is encoded by the CTNNA1 gene. αE-catenin is highly expressed in cardiac muscle and localizes to adherens junctions at intercalated disc structures where it functions to mediate the anchorage of actin filaments to the sarcolemma. αE-catenin also plays a role in tumor metastasis and skin cell function.
Tight junction protein ZO-3 is a protein that in humans is encoded by the TJP3 gene.
Cingulin-like protein 1, also known as paracingulin or junction-associated-coiled-coil protein (JACOP), is a protein which is encoded by the CGNL1 gene.