Sterols regulate processing of carbohydrate chains of wild-type SREBP cleavage-activating protein (SCAP), but not sterol-resistant mutants Y298C or D443N.

ABSTRACT: SREBP cleavage activating protein (SCAP), a membrane-bound glycoprotein, regulates the proteolytic activation of sterol regulatory element binding proteins (SREBPs), which are membrane-bound transcription factors that control lipid synthesis in animal cells. SCAP-stimulated proteolysis releases active fragments of SREBPs from membranes of the endoplasmic reticulum and allows them to enter the nucleus where they activate transcription. Sterols such as 25-hydroxycholesterol inactivate SCAP, suppressing SREBP proteolysis and turning off cholesterol synthesis. We here report the isolation of Chinese hamster ovary cells with a point mutation in SCAP (Y298C) that renders the protein resistant to inhibition by 25-hydroxycholesterol. Like the previously described D443N mutation, the Y298C mutation

SUBMITTER: Nohturfft A 

PROVIDER: S-EPMC23627 | biostudies-literature | 1998 Oct

REPOSITORIES: biostudies-literature