Occludin (OCLN)

Occludin is an integral membrane protein (~65 kDa) localized primarily at the tight junctions between epithelial and endothelial cells. It plays a central role in regulating paracellular permeability by forming part of the physical seal between adjacent cells. Occludin has four transmembrane domains with two extracellular loops critical for cell-cell adhesion. Its cytoplasmic C-terminal domain interacts with scaffolding proteins like ZO‑1/ZO‑2/ZO‑3 and F-actin to anchor it within the cellular architecture. Beyond its structural role at tight junctions, recent evidence suggests that occludin also participates in cell signaling pathways affecting metabolism and gene expression. Disruption or downregulation of occludin contributes to various pathologies involving compromised tissue barriers—including neurological disorders linked to genetic mutations in OCLN—and serves as an essential co-receptor facilitating hepatitis C virus entry into hepatocytes. Multiple isoforms exist due to alternative splicing; post-translational modifications such as phosphorylation regulate its localization/functionality within tissues.

Other names

OCLNTight junction protein occludin

For experimental drugs/agents targeting occludin or its pathway: - Modulation of tight junction integrity/permeability - Inhibition of viral entry by blocking co-receptor function for HCV