Structural basis of internal Vangl2 peptide recognition by the Dvl2 PDZ domain

Abstract

Planar cell polarity (PCP) signaling is an evolutionarily conserved pathway that regulates cellular asymmetry and tissue organization during development and homeostasis. Dysregulation of PCP signaling is associated with developmental defects and human diseases, highlighting its essential biological functions. Core PCP proteins, including Van Gogh-like 2 (Vangl2) and Dishevelled (Dvl), form dynamic molecular complexes through regulated protein–protein interactions to control PCP signal transduction [1]. PDZ domains typically recognize short C-terminal peptide motifs (PDZ-binding motifs, PBMs) through interactions involving the terminal carboxyl group. However, structural studies have demonstrated that certain PDZ domains, including Dvl PDZ domains, can also recognize internal peptide sequences, revealing broader ligand recognition capabilities [2]. Although Dvl PDZ domains are capable of binding internal ligands, the structural basis underlying recognition of an internal Vangl2 sequence remains unclear. Here, we identify an internal Vangl2 peptide (residues 302–311) as a direct binding element for the Dvl2 PDZ domain and define the molecular basis of this interaction through X-ray crystallography, quantitative binding analyses, reciprocal mutagenesis, and cellular validation. To identify the region of Vangl2 responsible for Dvl2 binding, we performed truncation mapping using pull-down assays. Progressive deletion analysis identified residues 292–340 within the cytoplasmic region of Vangl2 as the minimal region required for interaction with the Dvl2 PDZ domain (Fig. 1a). Further analysis demonstrated that the internal sequence spanning residues 302–311 is critical for recognition. We