OCLN

Description

The OCLN (occludin) is a protein-coding gene located on chromosome 5.

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.

== Gene location == In humans is encoded by the OCLN gene located on the long (q) arm of chromosome 5 at position q13.1. The canonical gene is 65,813 base pairs long, spanning base pairs 69,492,292 to 69,558,104. Its product is 522 amino acids long.

== Protein structure == Occludin's structure can be broken down into 9 domains.

Occludin contributes to the formation and control of the tight junction (TJ) paracellular barrier, which regulates the passage of molecules between cells. It can induce cell adhesion even in cells that normally lack tight junctions.

OCLN is also known as BLCPMG, PPP1R115, PTORCH1.

Associated Diseases

• Congenital intrauterine infection-like syndrome
• Band-Like calcification with simplified gyration and polymicrogyria