second protein kinase C conserved region 1 (C1 domain) found in uncharacterized phosphatidylinositol 3-kinase regulatory subunit-like proteins
The family includes a group of uncharacterized proteins that show high sequence similarity to vertebrate phosphatidylinositol 3-kinase regulatory subunits (PIK3Rs), which bind to activated (phosphorylated) protein-tyrosine kinases through its SH2 domain and regulate their kinase activity. Unlike typical PIK3Rs, members of this family have two C1 domains. This model corresponds to the second one. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites.