Component of the TSC-TBC complex, that contains TBC1D7 in addition to the TSC1-TSC2 complex and consists of the functional complex possessing GTPase-activating protein (GAP) activity toward RHEB in response to alterations in specific cellular growth conditions. The small GTPase RHEB is a direct activator of the protein kinase activity of mTORC1 and the TSC-TBC complex acts as a negative regulator of mTORC1 signaling cascade by acting as a GAP for RHEB. Participates in the proper sensing of growth factors and glucose, but not amino acids, by mTORC1. It is unclear whether TBC1D7 acts as a GTPase-activating protein and additional studies are required to answer this question (By similarity). Component of the TSC-TBC complex (also named Rhebulator complex), composed of the TSC1-TSC2 heterodimer and TBC1D7. Interacts with TSC1 (via C-terminal half of the coiled-coil domain) (By similarity). Localizes in the cytoplasmic vesicles of the endomembrane in association with TSC1-TSC2 complex.