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

Mol Cell. 1998 Oct;2(4):505-14. doi: 10.1016/s1097-2765(00)80150-1.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alkaline Phosphatase / genetics
  • Alkaline Phosphatase / metabolism*
  • Amino Acid Sequence
  • Animals
  • Blotting, Northern
  • Blotting, Southern
  • CCAAT-Enhancer-Binding Proteins*
  • CHO Cells
  • Cloning, Molecular
  • Cricetinae
  • DNA, Complementary
  • DNA-Binding Proteins / metabolism*
  • Humans
  • Molecular Sequence Data
  • Mutagenesis
  • Nuclear Proteins / metabolism*
  • Open Reading Frames / genetics
  • Placenta / enzymology
  • Proprotein Convertases*
  • RNA, Messenger / analysis
  • Recombinant Fusion Proteins / metabolism
  • Serine Endopeptidases / genetics*
  • Serine Endopeptidases / metabolism
  • Sterol Regulatory Element Binding Protein 1
  • Sterols / metabolism*
  • Subtilisins / genetics
  • Subtilisins / metabolism
  • Transcription Factors / metabolism*
  • Transfection

Substances

  • CCAAT-Enhancer-Binding Proteins
  • DNA, Complementary
  • DNA-Binding Proteins
  • Nuclear Proteins
  • RNA, Messenger
  • Recombinant Fusion Proteins
  • SREBF1 protein, human
  • Sterol Regulatory Element Binding Protein 1
  • Sterols
  • Transcription Factors
  • Alkaline Phosphatase
  • Proprotein Convertases
  • Serine Endopeptidases
  • Subtilisins
  • membrane-bound transcription factor peptidase, site 1

Associated data

  • GENBANK/AF078105