A Van Gogh/Vangl tyrosine phosphorylation switch regulates its interaction with core Planar Cell Polarity factors Prickle and Dishevelled

Abstract

Epithelial tissues can be polarized along two axes, in addition to apical-basal polarity they are often also polarized within the plane of the epithelium, known as planar cell polarity (PCP). PCP depends upon the conserved Wnt/Frizzled (Fz) signaling factors, including Fz itself and Van Gogh (Vang/Vangl). Here, taking advantage of the complementary features of Drosophila wing and mouse skin PCP establishment, we dissect how Vang phosphorylation on a specific conserved tyrosine residue affects its interaction with two cytoplasmic core PCP factors, Dsh/Dvl and Pk. We demonstrate that Pk and Dsh/Dvl bind to Vang/Vangl in an overlapping region centered around this tyrosine. Strikingly, Vang/Vangl2 phosphorylation promotes its binding to Pk, a key effector of the Vang/Vangl complex, and inhibits its interaction with Dsh/Dvl, and thus phosphorylation of this tyrosine appears to promote the formation of the mature and stable Vang/Vangl-Pk complex during PCP establishment. Interestingly, as our single point mutations allow selective binding inhibition of either Dsh or Pk, we can demonstrate for the first time that Dsh interaction with Vang is physiologically important, as all single point mutations fail to rescue the Vang null mutant wing phenotype.

Protein phosphatase 1 regulates core PCP signaling

“…phosphorylation is a modest fraction of the total phosphorylation of Vang in vivo, making it difficult to detect. Treatment with the dual serine/threonine and tyrosine-specific lambda phosphatase reveals significant phosphorylation of Vang in vivo, and tyrosine phosphorylation of Vang has also been demonstrated (Humphries et al, 2023).…”

“…Of note, the MS analysis identified tyrosine phosphorylation (Y473) that was shown to be mediated by the Abl kinase and to have a relatively PCP‐specific requirement, as a Y473F mutant behaves much like the PCP‐specific dsh 1 allele (Singh et al , 2010; Yanfeng et al , 2011). Tyrosine phosphorylations have been proposed to regulate additional aspects of PCP signaling as well (Guo et al , 2013; Kelly et al , 2016; Humphries et al , 2023).…”

“…It is also likely that the contribution of Dco‐dependent phosphorylation is a modest fraction of the total phosphorylation of Vang in vivo , making it difficult to detect. Treatment with the dual serine/threonine and tyrosine‐specific lambda phosphatase reveals significant phosphorylation of Vang in vivo , and tyrosine phosphorylation of Vang has also been demonstrated (Humphries et al , 2023). The subtle shift in phosphorylation we detect with Pp1‐87B overexpression, and lack of shift upon knockdown, are consistent with the possibility that Pp1‐87B phosphatase activity, in conjunction with pertinent regulatory components, acts on a limited set of Vang phosphorylation sites in the context of PCP signaling in vivo .…”

Protein phosphatase 1 regulates core PCP signaling

“…Of note, the MS analysis identified a tyrosine phosphorylation (Y473) that was shown to be mediated by the Abl kinase and to have a relatively PCP-specific requirement, as a Y473F mutant behaves much like the PCP-specific dsh 1 allele (Singh et al , 2010; Yanfeng et al ., 2011). Tyrosine phosphorylations have been proposed to regulate additional aspects of PCP signaling as well (Guo Zanetti & Schekman, 2013; Humphries et al , 2023; Kelly et al ., 2016).…”

Prickle and Ror modulate Dishevelled-Vangl interaction to regulate non-canonical Wnt signaling during convergent extension

“…We, however, do not favor this possibility because 1) the binding between Pk and Dvl was reported to be quite weak (Bastock et al, 2003); 2) our unpublished data show that ΔPL, a Pk mutant lacking the PET/LIM domains necessary for Dvl binding (Takeuchi et al, 2003), can largely mimic wild-type Pk function. Furthermore, a new study in flies showed that the phosphorylation status of a conserved tyrosine in the cytoplasmic tail of Vang provides opposite binding preference for Pk and Dsh, suggesting that simultaneous binding of both Pk and Dsh to the C-terminus of Vang may not be possible (Humphries et al, 2023).…”