PDZ2 domain of zonula occludens-1 and -2 is a phosphoinositide binding domain

• Published in: Cellular and molecular life sciences : CMLS Vol. 66; no. 24; pp. 3951 - 3966
• Main Authors: Meerschaert, Kris, Tun, Moe Phyu, Remue, Eline, De Ganck, Ariane, Boucherie, Ciska, Vanloo, Berlinda, Degeest, Gisèle, Vandekerckhove, Joël, Zimmermann, Pascale, Bhardwaj, Nitin, Lu, Hui, Cho, Wonhwa, Gettemans, Jan
• Format: Journal Article
• Language: English
• Published: Basel Basel : SP Birkhäuser Verlag Basel 01.12.2009; SP Birkhäuser Verlag Basel; Springer Nature B.V
• Subjects: Amino Acid Substitution; Animals; Binding Sites; Biochemistry; Biomedical and Life Sciences; Biomedicine; Blotting, Western; Cell Biology; Cell Line; Cell Line, Tumor; Cell Membrane - metabolism; Cell Nucleus - metabolism; Cellular biology; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; HeLa Cells; Humans; Life Sciences; Lipids; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; Microscopy, Fluorescence; Models, Molecular; Mutation; PDZ Domains; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositol Phosphates - metabolism; Phosphatidylinositols - chemistry; Phosphatidylinositols - metabolism; Phosphoproteins - chemistry; Phosphoproteins - genetics; Phosphoproteins - metabolism; Protein Binding; Protein Structure, Tertiary; Proteins; Research Article; RNA Interference; Surface Plasmon Resonance; Zonula Occludens-1 Protein; Zonula Occludens-2 Protein; Phospholipid; Post synaptic density-discs large-zonula occludens; Nucleus; Tight junction; Cell polarity
• ISSN: 1420-682X; 1420-9071
• DOI: 10.1007/s00018-009-0156-6

Zonula occludens proteins (ZO) are postsynaptic density protein-95 discs large-zonula occludens (PDZ) domain-containing proteins that play a fundamental role in the assembly of tight junctions and establishment of cell polarity. Here, we show that the second PDZ domain of ZO-1 and ZO-2 binds phosphoinositides (PtdInsP) and we identified critical residues involved in the interaction. Furthermore, peptide and PtdInsP binding of ZO PDZ2 domains are mutually exclusive. Although lipid binding does not seem to be required for plasma membrane localisation of ZO-1, phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P ₂) binding to the PDZ2 domain of ZO-2 regulates ZO-2 recruitment to nuclear speckles. Knockdown of ZO-2 expression disrupts speckle morphology, indicating that ZO-2 might play an active role in formation and stabilisation of these subnuclear structures. This study shows for the first time that ZO isoforms bind PtdInsPs and offers an alternative regulatory mechanism for the formation and stabilisation of protein complexes in the nucleus.