AKT is a widely expressed serine/threonine-specific kinase with key roles in cell signaling in response to extracellular stimuli. AKT signaling serves to regulate cell physiology such as survival, growth and metabolism. AKT is a major target of the PI3Kinase and is hyper-activated in metabolic diseases and cancer. Therefore, there are ongoing efforts to find therapeutic targets of AKT. Mechanism of AKT activation has been extensively studied and full AKT activation requires both the phosphorylation of Thr308 and Ser473. Although the PDK1 (phosphoinositide-dependent kinase)-mediated AKT phosphorylation at Thr308 has been well studied, the mechanism of mTORC2 leading AKT activation at Ser473 remains elusive. To assess the role of regulators for mTORC2, we analyzed the dynamics of mammalian stress-activated map kinase-interacting (mSIN) which is necessary for the assembly of mTORC2. Immunofluorescence imaging showed that mSIN is localized in the early endosomes containing fluorescent EGFs endocytosed and Rab5 which is an early endosomal marker. Super-resolution imaging demonstrated the interaction between mSIN and constitutively active Rab5 (Rab5-Q79L) is indirect. Biochemical experiment also demonstrated that GST-EEA1-RBD (Rab5 binding domain) bound active Rab5 endosome interacts with the mSIN and Rictor. Next, we investigated what factors mediate mTORC2 translocation into the early endosomes. Partial co-localization of mSIN-RBD-PH domain with AKT-PH domain (a sensor for PtdIns(3,4,5)P3 and PtdIns(3,4)P2) inside the plasma membrane provides the possibility that mSIN-RBD-PH could interact with PtdIns(3,4)P2 in the endosomes. To confirm the association of mSIN with endosomal PtdIns(3,4)P2, we demonstrated the co-localization of mSIN and PtdIns(3,4)P2 via antibody to PtdIns(3,4)P2. We also observed lysosomal degradation of Rictor, a component of mTORC2. In conclusion, we propose that AKT activation by mTORC2 in the early endosome is critical for receptor-mediated signal propagation to the cytosol.