In complex with TSC1, this tumor suppressor inhibits the nutrient-mediated or growth factor-stimulated phosphorylation of S6K1 and EIF4EBP1 by negatively regulating mTORC1 signaling (By similarity). Acts as a GTPase-activating protein (GAP) for the small GTPase RHEB, a direct activator of the protein kinase activity of mTORC1 (By similarity). May also play a role in microtubule-mediated protein transport (PubMed:16707451). Also stimulates the intrinsic GTPase activity of the Ras-related proteins RAP1A and RAB5 (By similarity). Probably forms a complex composed of chaperones HSP90 and HSP70, co-chaperones STIP1/HOP, CDC37, PPP5C, PTGES3/p23, TSC1 and client protein TSC2 (By similarity). Probably forms a complex composed of chaperones HSP90 and HSP70, co-chaperones CDC37, PPP5C, TSC1 and client protein TSC2, CDK4, AKT, RAF1 and NR3C1; this complex does not contain co-chaperones STIP1/HOP and PTGES3/p23 (By similarity). Forms a complex containing HSP90AA1, TSC1 and TSC2; TSC1 is required to recruit TCS2 to the complex thereby stabilizing TSC2 (By similarity). Interacts with TSC1 and HERC1; the interaction with TSC1 stabilizes TSC2 and prevents the interaction with HERC1 (By similarity). May also interact with the adapter molecule RABEP1 (By similarity). The final complex may contain TSC2 and RABEP1 linked to RAB5 (By similarity). Interacts with HSPA1 and HSPA8 (By similarity). Interacts with DAPK1 (By similarity). Interacts with FBXW5 (By similarity). Interacts with NAA10 (via C-terminal domain) (By similarity). Interacts with RRAGA (polyubiquitinated) (By similarity). Interacts with WDR45B (By similarity). Interacts with RPAP3 and URI1 (By similarity). Interacts with YWHAG (By similarity). At steady state found in association with membranes. Widely expressed. Phosphorylation at Ser-1388, Ser-1419 or Ser-1421 does not affect interaction with TSC1. Phosphorylation at Ser-939 and Thr-1465 by PKB/AKT1 is induced by growth factor stimulation. Phosphorylation by AMPK activates it and leads to negative regulation of the mTORC1 complex. Phosphorylated at Ser-1805 by RPS6KA1; phosphorylation inhibits TSC2 ability to suppress mTORC1 signaling. Phosphorylated by DAPK1. Ubiquitinated by the DCX(FBXW5) E3 ubiquitin-protein ligase complex, leading to its subsequent degradation. Ubiquitinated by MYCBP2 independently of its phosphorylation status leading to subsequent degradation; association with TSC1 protects from ubiquitination.