Nuclear VANGL2 Inhibits Lactogenic Differentiation

Abstract

ABSTRACTPlanar cell polarity (PCP) proteins coordinate tissue morphogenesis by governing cell patterning and polarity. Asymmetrically localized on the plasma membrane of cells, PCP proteins are also trafficked by endocytosis, suggesting they may have intracellular functions that are dependent or independent of their extracellular role, but whether these functions extend to transcriptional control remains unknown. Here, we show the nuclear localization of transmembrane, PCP protein, VANGL2, in undifferentiated, but not differentiated, HC11 cells, which serve as a model for mammary lactogenic differentiation. Loss ofVangl2function results in upregulation of pathways related to STAT5 signaling. We identify DNA binding sites and a nuclear localization signal in VANGL2, and use CUT&RUN to demonstrate direct binding of VANGL2 to specific DNA binding motifs, including one in theStat5apromoter. Knockdown (KD) ofVangl2in HC11 cells and primary mammary organoids results in upregulation ofStat5a,Ccnd1andCsn2, larger acini and organoids, and precocious differentiation; phenotypes rescued by overexpression ofVangl2, but notVangl2ΔNLS. Together, these results advance a paradigm whereby PCP proteins coordinate tissue morphogenesis by keeping transcriptional programs governing differentiation in check.