TY - JOUR
T1 - Crucial step in cholesterol homeostasis
T2 - Sterols promote binding of SCAP to INSIG-1, a membrane protein that facilitates retention of SREBPs in ER
AU - Yang, Tong
AU - Espenshade, Peter J.
AU - Wright, Michael E.
AU - Yabe, Daisuke
AU - Gong, Yi
AU - Aebersold, Ruedi
AU - Goldstein, Joseph L.
AU - Brown, Michael S.
N1 - Funding Information:
We thank our colleague Andrew Brown for helpful discussions; Debra Morgan, Tammy Dinh, and Carla Dorsett for excellent technical assistance; Lisa Beatty and Angela Carroll for invaluable help with tissue culture; Jeff Cormier and Melody Kerr for DNA sequencing; and Drs. Randy Schekman and Marcus Lee for suggesting use of BN-PAGE and providing protocols. While these studies were in progress, Drs. Bethany Janowski and David W. Russell observed independently that transfected INSIG-1 blocks SREBP processing in transfected cells. This work was supported by grants from the National Institutes of Health (HL-20948 and 1R33CA-84698), Perot Family Foundation, and Keck Foundation. A gift from Merck and Co. to support research at the Institute for Systems Biology is gratefully acknowledged. P.J.E. is the recipient of a Burroughs Welcome Fund Career Award in the Biomedical Sciences. M.E.W. is the recipient of a NIH Postdoctoral Genome Training Fellowship Grant and was supported in part by an UNCF/Merck postdoctoral fellowship.
PY - 2002/8/23
Y1 - 2002/8/23
N2 - Using coimmunoprecipitation and tandem mass spectrometry, we identify INSIG-1 as an ER protein that binds the sterol-sensing domain of SREBP cleavage-activating protein (SCAP) and facilitates retention of the SCAP/SREBP complex in the ER. In sterol-depleted cells, SCAP escorts SREBPs from ER to Golgi for proteolytic processing, thereby allowing SREBPs to stimulate cholesterol synthesis. Sterols induce binding of SCAP to INSIG-1, as determined by blue native-PAGE, and this is correlated with the inhibition of SCAP exit from the ER. Overexpression of INSIG-1 increases the sensitivity of cells to sterol-mediated inhibition of SREBP processing. Mutant SCAP(Y298C) fails to bind INSIG-1 and is resistant to sterol-mediated inhibition of ER exit. By facilitating sterol-dependent ER retention of SCAP, INSIG-1 plays a central role in cholesterol homeostasis.
AB - Using coimmunoprecipitation and tandem mass spectrometry, we identify INSIG-1 as an ER protein that binds the sterol-sensing domain of SREBP cleavage-activating protein (SCAP) and facilitates retention of the SCAP/SREBP complex in the ER. In sterol-depleted cells, SCAP escorts SREBPs from ER to Golgi for proteolytic processing, thereby allowing SREBPs to stimulate cholesterol synthesis. Sterols induce binding of SCAP to INSIG-1, as determined by blue native-PAGE, and this is correlated with the inhibition of SCAP exit from the ER. Overexpression of INSIG-1 increases the sensitivity of cells to sterol-mediated inhibition of SREBP processing. Mutant SCAP(Y298C) fails to bind INSIG-1 and is resistant to sterol-mediated inhibition of ER exit. By facilitating sterol-dependent ER retention of SCAP, INSIG-1 plays a central role in cholesterol homeostasis.
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U2 - 10.1016/S0092-8674(02)00872-3
DO - 10.1016/S0092-8674(02)00872-3
M3 - Article
C2 - 12202038
AN - SCOPUS:0037162719
SN - 0092-8674
VL - 110
SP - 489
EP - 500
JO - Cell
JF - Cell
IS - 4
ER -