FIGURE 8.

Structural comparison of the TSC1-TBC1D7 complex with a TBC-domain/Rab-GTPase complex. a, the TSC1-TBC1D7 complex structure superimposed with that of a Rab-TBC complex between Rab33 and the TBC domain of Gyp1p (PDB code 2G77). Colors of the individual molecules are indicated. b, a close-up view of the GAP active site. GDP-aluminum fluoride, which mimics the transition state of GTP, and the two catalytic residues (Arg³⁴³ and Gln³⁷⁸) are shown for the Rab-TBC complex. TBC1D7 lacks these two critical residues and has a very different structure to other TBC domains.