PRNP and childhood gender nonconformity: However, because among all tested SFK members Fyn is the only one co-migrating with the immunolabelled p-SFK band (Supplementary Figure 4), we can conclude that the observed p-SFK (Figure 2A and Supplementary Figure 3) corresponds to p-Fyn, and consequently, that PrPC downregulates Fyn in CGN.