Fig. 1

PI3Ks are classified based on their substrate specificities and structures. Class IA and IB PI3Ks phosphorylate PtdIns(4,5)P2, while class III PI3Ks phosphorylate PtdIns. Class II PI3Ks may also preferentially phosphorylate PtdIns. Class IA PI3Ks consist of p110 catalytic subunits and p85 regulatory subunits, with specific domains such as p85-BD, RBD, helical, and catalytic domains. Class IB PI3Ks comprise p110γ catalytic subunits and p101 or p87 regulatory subunits. Class II PI3Ks, including PI3K-C2α, PI3K-C2β, and PI3K-C2γ, have monomeric structures. The only class III PI3K is VPS34, which forms a heterodimer with VPS15 and possesses helical and catalytic domains. Various domains, such as P domains and C2 domains, are also indicated in their structures