Component of a Ras-regulated pathway involved in integrating chemotaxis and signal relay pathways that are essential for aggregation. Interacts with activated RasG. Part of a complex, TORC2, consisting of tor, lst8, piaA and ripA. Additional proteins, such as 14-3-3 and heat-shock proteins, may also belong to the TORC2 complex. Null cells have serious developmental defects, because they are unable to activate the aggregation-stage adenylyl cyclase acaA in response to chemoattractant and are defective in chemotaxis. Cells are unable to properly polarize in a cAMP gradient. Belongs to the SIN1 family.