Deubiquitination of Vangl by USP6 and USP32 Regulates Planar Cell Polarity Signaling.

Planar cell polarity (PCP) signaling is an evolutionarily conserved mechanism regulating polarized cellular and tissue behaviors in diverse morphogenetic and physiological processes. Disruption or aberrant activation of PCP signaling can cause developmental defects or promote cancer malignancy. Vangl1 and Vangl2 are redundant core PCP components, and their protein levels are tightly controlled to maintain appropriate PCP signaling. Here, we identify two deubiquitinases, USP6 and USP32, that stabilize Vangl proteins through distinct ubiquitin linkage-specific mechanisms. USP6 primarily removes K33-linked and multi-monoubiquitin signals from plasma membrane-associated Vangl2, whereas USP32 removes K48-linked ubiquitin chains from Golgi/ER-localized Vangl2, thereby regulating distinct subcellular pools of Vangl2. Given that USP6 was previously reported to be a hominoid-specific gene originating from USP32, our findings suggest evolutionary refinement in PCP regulation. Consistent with these biochemical functions, genetic interaction studies demonstrate that Usp32 cooperates with Vangl genes to regulate PCP signaling during mouse embryogenesis. In pancreatic ductal adenocarcinoma, USP32 and VANGL1 are markedly upregulated and functionally promote cancer cell migration and metastasis. USP32 enhances metastatic behavior by stabilizing VANGL1 proteins. Together, our findings uncover a previously unrecognized regulatory mechanism of PCP signaling through USP6/USP32-mediated deubiquitination of Vangl proteins and highlight its roles in both developmental morphogenesis and cancer progression.