The comparison between BSD functional domain of FRG4 and PDZ, SH3, GK functional domain of SAP family showed that their homogeneity was lower than 10% .

• FRG4编码蛋白形成突触相关蛋白家族(SAP家族)一个独立的分支,FRG4的BSD功能域与SAP家族的PDZ,SH3,GK功能域比较。