Identification of two SH3-binding motifs in the regulatory subunit of phosphatidylinositol 3-kinase.

摘要: Src homology 3 (SH3) domains have been recently shown to bind proline-rich sequences contained in 3BP1, 3BP2, and SOS. In a recent study we demonstrated that phosphatidylinositol 3-kinase (PI 3-kinase) associates with the Fyn SH3 domain. Here show p85, regulatory subunit of PI 3-kinase, binds directly Abl, Lck, Fyn, p85 itself. An examination amino acid sequence revealed two its N-terminal region similar those present To test whether these mediate association peptides composition corresponding alpha were synthesized used competition assays. Both worked equally well inhibiting binding activity domain, whereas control peptide had no effect. These results indicate that, as 3BP1 SOS, interaction domains. also suggest domain may "self-associate" motifs same part mechanism.