Molecular identification of the sterol-regulated luminal protease that cleaves SREBPs and controls lipid composition of animal cells

Juro Sakai, Robert B. Rawson, Peter J. Espenshade, Dong Cheng, Adam C. Seegmiller, Joseph L. Goldstein, Michael S. Brown

Research output: Contribution to journalArticle

295 Scopus citations


The lipid composition of animal cells is controlled by SREBPs, transcription factors released from membranes by sterol-regulated proteolysis. Release is initiated by Site-1 protease (S1P), which cleaves SREBPs in the ER luminal loop between two membrane-spanning regions. To clone S1P, we prepared pCMV-PLAP-BP2, which encodes a fusion protein that contains placental alkaline phosphatase (PLAP) in the ER lumen flanked by cleavage sites for signal peptidase and S1P. In sterol-deprived cells, cleavage by both proteases leads to PLAP secretion. PLAP is not secreted by SRD-12B cells, cholesterol auxotrophs that lack S1P. We transfected SRD-12B cells with pCMV-PLAP-BP2 plus pools of CHO cDNAs and identified a cDNA that restores Site-1 cleavage and PLAP secretion. The cDNA encodes S1P, an intraluminal 1052-amino-acid membrane-bound subtilisin-like protease. We propose that S1P is the sterol-regulated protease that controls lipid metabolism in animal cells.

Original languageEnglish (US)
Pages (from-to)505-514
Number of pages10
JournalMolecular cell
Issue number4
StatePublished - Oct 1998


ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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