Format

Send to

Choose Destination
J Biol Chem. 2014 Mar 14;289(11):7547-57. doi: 10.1074/jbc.M113.545699. Epub 2014 Jan 29.

Sterol regulatory element-binding protein (SREBP) cleavage regulates Golgi-to-endoplasmic reticulum recycling of SREBP cleavage-activating protein (SCAP).

Author information

1
From the Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.

Abstract

Sterol regulatory element-binding protein (SREBP) transcription factors are central regulators of cellular lipogenesis. Release of membrane-bound SREBP requires SREBP cleavage-activating protein (SCAP) to escort SREBP from the endoplasmic reticulum (ER) to the Golgi for cleavage by site-1 and site-2 proteases. SCAP then recycles to the ER for additional rounds of SREBP binding and transport. Mechanisms regulating ER-to-Golgi transport of SCAP-SREBP are understood in molecular detail, but little is known about SCAP recycling. Here, we have demonstrated that SCAP Golgi-to-ER transport requires cleavage of SREBP at site-1. Reductions in SREBP cleavage lead to SCAP degradation in lysosomes, providing additional negative feedback control to the SREBP pathway. Current models suggest that SREBP plays a passive role prior to cleavage. However, we show that SREBP actively prevents premature recycling of SCAP-SREBP until initiation of SREBP cleavage. SREBP regulates SCAP in human cells and yeast, indicating that this is an ancient regulatory mechanism.

KEYWORDS:

Cholesterol; Lipids; Lysosomes; Protein Degradation; Recycling; SCAP; SREBP; Transcription Factors

PMID:
24478315
PMCID:
PMC3953268
DOI:
10.1074/jbc.M113.545699
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center