Spatial Overlap of Claudin- and Phosphatidylinositol Phosphate-Binding Sites on the First PDZ Domain of Zonula Occludens 1 Studied by NMR

• Published in: Molecules (Basel, Switzerland) Switzerland), 2018-09, Vol.23 (10), p.2465
• Main Authors: Hiroaki, Hidekazu, Satomura, Kaori, Goda, Natsuko, Nakakura, Yukako, Hiranuma, Minami, Tenno, Takeshi, Hamada, Daizo, Ikegami, Takahisa
• Format: Article
• Language: English
• Subjects: Animals; Binding Sites; chemical shift perturbation; Claudins - metabolism; Magnetic Resonance Imaging - methods; Mice; Mutation; NMR; PDZ domain; PDZ Domains; Phosphatidylinositol Phosphates - metabolism; phosphoinositide; Protein Binding; protein-phospholipid interaction; tight junction; Tight Junctions - metabolism; Zonula Occludens-1 Protein - chemistry; Zonula Occludens-1 Protein - genetics; Zonula Occludens-1 Protein - metabolism
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules23102465

: The tight junction is an intercellular adhesion complex composed of claudins (CLDs), occludin, and the scaffolding proteins zonula occludens 1 (ZO-1) and its two paralogs ZO-2 and ZO-3. ZO-1 is a multifunctional protein that contains three PSD95/Discs large/ZO-1(PDZ) domains. A key functional domain of ZO-1 is the first PDZ domain (ZO-1(PDZ1)) that recognizes the conserved C-termini of CLDs. : In this study, we confirmed that phosphoinositides bound directly to ZO-1(PDZ1) by biochemical and solution NMR experiments. We further determined the solution structure of mouse ZO-1(PDZ1) by NMR and mapped the phosphoinositide binding site onto its molecular surface. : The phosphoinositide binding site was spatially overlapped with the CLD-binding site of ZO-1(PDZ1). Accordingly, inositol-hexaphosphate (phytic acid), an analog of the phosphoinositide head group, competed with ZO-1(PDZ)-CLD interaction. : The results suggested that the PDZ domain⁻phosphoinositide interaction plays a regulatory role in biogenesis and homeostasis of the tight junction.