Sterol-sensing domain (IPR000731)

Short name: SSD

Overlapping homologous superfamilies


Domain relationships



The sterol-sensing domain (SSD) is an around 180 residues long cluster of five membrane-spanning segments. The SSD domain is conserved across phyla and confers sensitivity to regulation by sterol. Although the SSD domain appears to function as a regulatory domain involved in linking vesicle trafficking and protein localization with such varied processes as cholesterol homeostasis, cell signalling and cytokinesis, its exact mode of action is not clear. It is not known whether it interacts with sterols, such as cholesterol, or whether it interacts with another-sterol regulated protein. Alternatively, the SSD may interact with lipids other than cholesterol [PMID: 9642295, PMID: 10821832, PMID: 11932020].

In addition to the proteins above, the SSD is also found in a number of bacterial drug resistance proteins.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles