Tight junction protein claudin-1 (CLDN1)

Tight junction protein claudin-1 (CLDN1) is a transmembrane protein belonging to the claudin family, which are essential components of tight junctions in epithelial and endothelial cells[1][2][4]. Claudin-1 consists of four transmembrane domains, two extracellular loops, and cytoplasmic N- and C-termini, with its C-terminus containing a PDZ domain-binding motif for interactions with scaffolding proteins like ZO-1[1][4]. CLDN1 plays a critical role in regulating paracellular barrier permeability, maintaining cell–cell adhesion, tissue homeostasis, and modulating signaling pathways relevant to cell growth and differentiation[1][4]. Its deregulated expression is a hallmark in several cancers, where it acts as either a tumor promoter or suppressor depending on context, affects metastasis, and is under investigation as a therapeutic target[2]. It is also significant in infection biology, as it serves as a co-receptor for hepatitis C virus entry. Drugs targeting claudin-1 or its complexes modulate tight junction function, with recent research focusing on specificity and safety of such agents for barrier reinforcement, cancer therapy, or antiviral strategies[3][4].

Other names

Claudin-1CLDN1Tight junction protein 1

Direct disruption or modulation of tight junctions; Induced change in paracellular permeability/barrier function[3]; Blocking viral entry (e.g., HCV)[2]