Fig. 1
From: Choroid plexus and the blood–cerebrospinal fluid barrier in disease
Schematic illustration of the anatomical organization of the CP (a) and the B-CSF barrier (b). The CP is an epithelio-endothelial convolute, comprising a highly vascularized stroma with connective tissue, and a continuous lining of epithelial cells with adhering Kolmer cells (a). The main site of the barrier (b) is at the level of the cuboidal epithelial cells that are linked by tight junctions (TJ), adherent junctions (AJ) and gap junctions (GJ). TJs are required for strong cell–cell adhesion and include transmembrane (occludin, claudins and JAMs) and cytoplasmic proteins (ZO). AJs are formed by E-cadherin, a transmembrane protein that intracellularly binds to actin through a variety of protein complexes, including catenin (p120, β-catenin, α-catenin). GJ protein complexes comprising nectin also play a role in adherence