Activates phosphatidylinositol 3-kinase when bound to the regulatory p85 subunit (By similarity). May mediate the control of various cellular processes by insulin-like peptides. When phosphorylated by the insulin receptor binds specifically to various cellular proteins containing SH2 domains. Involved in control of cell proliferation, cell size, and body and organ growth throughout development. Also has a role in a signaling pathway controlling the physiological response required to endure periods of low nutrient conditions. Insulin/insulin-like growth factor (IGF) signaling pathway has a role in regulating aging and is necessary in the ovary for vitellogenic maturation. Bindings to phosphatidylinositol 3-kinase and SHP2. Expressed during G1, S and G2 phase of the cell cycle. Female sterile. Extends fruit fly median life-span by up to 48% in homozygotes and 36% in heterozygotes. 'Chico' means 'small boy' in Spanish. Truncated N-terminus.