Table 1.

Ligands identified for the ORDs of human and Saccharomyces cerevisiae ORPs by structural analyses or in vitro binding/transport assays.

Protein	ORD ligand(s)	Reference(s)
Homo sapiens
OSBP	25OHC 1, 20OHC, 7KC 2, 22(R)OHC, 22(S)OHC, 7OHC, cholesterol + other oxysterols specified in [42]	[40,42,43,44]
ORP4/OSBP2	25OHC, 20OHC, 22(S)OHC, 7OHC, 7KC, 22(R)OHC, cholesterol	[43,61]
ORP1	24(S)OHC, 22(R)OHC, 7KC, 25OHC, cholesterol	[46,48]
ORP2	22(R)OHC, 7KC, 25OHC, cholesterol	[45,46]
ORP3	?
ORP5	Dehydroergosterol, cholesterol?, PS 3	[49,59]
ORP6	?
ORP7	?
ORP8	25OHC?, cholesterol	[62,63]
ORP9	Cholesterol	[50]
ORP10	Cholesterol, PS	[47,59]
ORP11	?
Saccharomyces cerevisiae
Osh1p	Cholesterol?	[38]
Osh2p	Cholesterol	[38]
Osh3p	PI4P 4, cholesterol?	[38,58]
Osh4p	Ergosterol, cholesterol, 7OHC, 20OHC, 25OHC, dehydroergosterol, PI4P, PIP2? PS?	[33,37,51]
Osh5p	Cholesterol	[38]
Osh6p	PS	[59]
Osh7p	PS	[59]

¹ hydroxycholesterol, ² ketocholesterol, ³ phosphatidylserine, ⁴ phosphatidylinositol-4-phosphate.