TJP1
Description
The TJP1 (tight junction protein 1) is a protein-coding gene located on chromosome 15.
TJP1, also known as Zonula occludens-1 (ZO-1), is a 220-kD peripheral membrane protein encoded by the TJP1 gene in humans. It belongs to the family of zonula occludens proteins (ZO-1, ZO-2, and ZO-3), which are tight junction-associated proteins. ZO-1 was the first protein in this family to be cloned. It was first isolated in 1986 using a monoclonal antibody that recognizes a 225-kD polypeptide in liver homogenates and tight junction-enriched membrane fractions. TJP1 acts as a scaffold protein that cross-links and anchors Tight Junction (TJ) strand proteins to the actin cytoskeleton. The protein is located on the cytoplasmic membrane surface of intercellular tight junctions and may be involved in signal transduction at cell–cell junctions. Two transcript variants encoding distinct isoforms have been identified for this gene.
TJP1, along with its close relatives TJP2 and TJP3, serves as a scaffolding protein within tight junctions (TJs). These junctions are crucial for controlling the passage of substances between cells and for maintaining distinct membrane domains in epithelial and endothelial cells. TJP1 links TJ transmembrane proteins, such as claudins, junctional adhesion molecules, and occludin, to the actin cytoskeleton, contributing to the integrity and function of TJs. TJP1 is essential for lumenogenesis and promotes efficient epithelial polarization and barrier formation. Additionally, TJP1 plays a role in cell migration by directing CDC42BPB to the leading edge of migrating cells, and it is involved in podosome formation, which regulates cell adhesion and matrix remodeling. In conjunction with TJP2 and TJP3, TJP1 contributes to the retention and stability of the transcription factor DBPA at the junction, but it does not participate in its nuclear transport.
TJP1 is also known as ZO-1.
