Shc promotes Gab2 tyrosine phosphorylation via Grb2 (Gu et al. 2000). This promotes binding of Gab2 to p85alpha, a component of Class 1A PI3Ks (Gu et al. 1998). JAK1 may also be involved in PI3K recruitment (Migone et al. 1998). Binding of p85 activates PI3K kinase activity, with consequent effects on many processes including Akt activation. This is one of two mechanisms described for the recruitment of PI3K to the IL-3/IL-5/GM-CSF receptors, the other is mediated by Serine-585 phosphorylation of the common beta chain.