Regulatory subunit of the PI3K gamma complex. Required for recruitment of the catalytic subunit to the plasma membrane via interaction with beta-gamma G protein dimers. Required for G protein-mediated activation of PIK3CG (By similarity). Greatly activated by G gamma proteins. Heterodimer. Interacts with a catalytic subunit and with beta-gamma G protein dimers (By similarity). The heterodimerization region allows the binding to the catalytic subunit.