Tetraspanin-12 (TSPAN12)

Plays a central role in retinal vascularization by regulating norrin (NDP) signal transduction. Acts in concert with norrin (NDP) to promote FZD4 multimerization and subsequent activation of FZD4, leading to promote accumulation of beta-catenin (CTNNB1) and excite LEF/TCF-mediated transcriptional programs.

Suprisingly, it only trigger the norrin (NDP)-dependent activation of FZD4, while it does not trigger the Wnt-dependent activation of FZD4, suggesting the occurrence of a Wnt-independent signaling that also promote accumulation the beta-catenin (CTNNB1) (By similarity). Acts as a regulator of membrane proteinases such as ADAM10 and MMP14/MT1-MMP.