C-terminal lipid-binding START domain of mammalian STARD8, -12, -13 and related proteins, which also have an N-terminal Rho GTPase-activating protein (RhoGAP) domain
This subfamily includes the steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domains of STARD8 (also known as deleted in liver cancer 3/DLC3, and Arhgap38), STARD12 (also known as DLC-1, Arhgap7, and p122-RhoGAP), and STARD13 (also known as DLC-2, Arhgap37, and SDCCAG13). The START domain family belongs to the SRPBCC (START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC) domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket. Proteins belonging to this subfamily also have a RhoGAP domain. Some, including STARD12, -and -13, also have an N-terminal SAM (sterile alpha motif) domain; these have a SAM-RhoGAP-START domain organization. This subfamily is involved in cancer development. A large spectrum of cancers have dysregulated genes encoding these proteins. The precise function of the START domain in this subfamily is unclear.