Molecular identification of the sterol-regulated luminal protease that cleaves SREBPs and controls lipid composition of animal cells
Molecular identification of the sterol-regulated luminal protease that cleaves SREBPs and controls lipid composition of animal cells
复制标题
DOI：
10.1016/s1097-2765(00)80150-1
复制
发表时间：
1998-10-01
期刊：
影响因子：
16
通讯作者：
Brown, MS
中科院分区：
文献类型：
--
作者：
Sakai, J;Rawson, RB;Brown, MS
动物细胞的脂质组成由SREBP控制，SREBP是通过固醇调节的蛋白水解从膜释放的转录因子。释放由位点-1蛋白酶（S1 P）启动，其切割两个跨膜区域之间的ER管腔环中的SREBP。为了克隆S1 P，我们制备了pCMV-PLAP-BP 2，其编码在ER腔中含有胎盘碱性磷酸酶（PLAP）的融合蛋白，所述ER腔两侧是信号肽酶和S1 P的切割位点。在甾醇缺乏的细胞中，两种蛋白酶的切割导致FLAP分泌。SRD-12 B细胞不分泌FLAP，SRD-12 B细胞是缺乏S1 P的胆固醇营养缺陷型。我们用pCMV-PLAP-BP 2加CHO cDNA库转染SRD-12 B细胞，并鉴定了恢复位点1切割和FLAP分泌的cDNA。该cDNA编码S1 P，一种管腔内1052个氨基酸的膜结合枯草杆菌蛋白酶样蛋白酶。我们建议，S1 P是固醇调节的蛋白酶，控制动物细胞中的脂质代谢。
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 FLAP secretion. FLAP 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 FLAP 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.