|PROSITE documentation PDOC50848 [for PROSITE entry PS50848]|
The StAR-related lipid-transfer (START) domain is an about 200-210 residue lipid-binding motif, which is primarily involved in eukaryotic signaling mediated by lipid binding. Representatives of the START domain family have been shown to bind different ligands such as sterols (StAR protein) and phosphatidylcholine (PC-TP). Ligand binding by the START domain can also regulate the activities of other domains that co-occur with the START domain in multidomain proteins such as Rho-GAP, the homeodomain (see <PDOC00027>), and the thioesterase domain [1,2].
The crystal structure of START domain of human MLN64 (see <PDB:1EM2>) shows an α/β fold built around an U-shaped incomplete β-barrel. Most importantly, the interior of the protein encompasses a 26 x 12 x 11 Angstroms hydrophobic tunnel that is apparently large enough to bind a single cholesterol molecule [3,4]. The START domain structure revealed an unexpected similarity to that of the birch pollen allergen Bet v 1 and to bacterial polyketide cyclases/aromatases [2,3].
Some proteins known to contain a START domain are listed below:
The profile we developed covers the entire START domain.Last update:
May 2002 / First entry.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Ponting C.P. Aravind L.|
|Title||START: a lipid-binding domain in StAR, HD-ZIP and signalling proteins.|
|Source||Trends Biochem. Sci. 24:130-132(1999).|
|2||Authors||Iyer L.M. Koonin E.V. Aravind L.|
|Title||Adaptations of the helix-grip fold for ligand binding and catalysis in the START domain superfamily.|
|3||Authors||Tsujishita Y. Hurley J.H.|
|Title||Structure and lipid transport mechanism of a StAR-related domain.|
|Source||Nat. Struct. Biol. 7:408-414(2000).|
|Title||StARTing to understand cholesterol transfer.|
|Source||Nat. Struct. Biol. 7:445-447(2000).|