Evidence map›Paper›PMID 41474747›Full record

ArticleProceedings of the National Academy of Sciences of the United States of America2026

Competition between a transmembrane helix on Scap and a membrane cholesterol regulates Scap-Insig interaction and SREBP activation.

Blake C Williams, Daniel L Kober, Xiao-Chen Bai, Daniel M Rosenbaum, Arun Radhakrishnan

Abstract read
In one paragraph

Article in Proceedings of the National Academy of Sciences of the United States of America, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Review
  2. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Blake C WilliamsDepartment of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390.ORCID 0000-0002-8537-4540
Daniel L KoberDepartment of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390.ORCID 0000-0001-8657-9348
Xiao-Chen BaiDepartment of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390.ORCID 0000-0002-4234-5686
Daniel M RosenbaumDepartment of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390.ORCID 0000-0002-7174-4993
Arun RadhakrishnanDepartment of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390.ORCID 0000-0002-7266-7336

Funding

Tissue Culture & Antibody Production CoreP01HL160487 · NHLBI · UT SOUTHWESTERN MEDICAL CENTER · PI Helen Haskell Hobbs · 2022 to 2026
$14.9M
UT Southwestern NORCP30DK127984 · NIDDK · UT SOUTHWESTERN MEDICAL CENTER · PI Jeff G McDonald · 2022 to 2026
$7.4M
Structural mechanisms of Scap/SREBP signaling in membrane homeostasisR35GM136387 · NIGMS · UT SOUTHWESTERN MEDICAL CENTER · PI Daniel Rosenbaum · 2020 to 2026
$3.0M
Oxysterol Regulation of Microbial PathogenesisR01AI158357 · NIAID · UT SOUTHWESTERN MEDICAL CENTER · PI ALTO, NEAL MATHEW, RADHAKRISHNAN, ARUN · 2021 to 2025
$2.9M
Molecular Biophysics Training ProgramT32GM131963 · NIGMS · UT SOUTHWESTERN MEDICAL CENTER · PI Luke W Rice · 2019 to 2026
$1.5M
Understanding general principles in receptor tyrosine kinase signaling through structural and functional studiesR35GM156386 · NIGMS · UT SOUTHWESTERN MEDICAL CENTER · PI Xiaochen Bai · 2025 to 2026
$1.1M
Structural and mechanistic basis for the maturation of site-one protease in the secretory pathwayR01GM155152 · NIGMS · UT SOUTHWESTERN MEDICAL CENTER · PI Daniel Luke Kober · 2024 to 2026
$1.0M
The mechanistic basis for targeted protein degradation in lipid metabolismR00GM141261 · NIGMS · UT SOUTHWESTERN MEDICAL CENTER · PI KOBER, DANIEL LUKE · 2023 to 2025
$747k
Structural and biophysical investigation of Scap regulation by cholesterolF31HL176187 · NHLBI · UT SOUTHWESTERN MEDICAL CENTER · PI Blake Christopher Williams · 2024 to 2026
$81k
HHS | NIH | National Heart, Lung, and Blood Institute (NHLBI) HL160487HHS | NIH | National Institute of General Medical Sciences (NIGMS) R35GM116387NHLBI NIH HHS F31 HL176187NHLBI NIH HHS P01 HL160487NIAID NIH HHS R01 AI158357NIDDK NIH HHS P30 DK127984NIGMS NIH HHS R00 GM141261NIGMS NIH HHS R01 GM155152NIGMS NIH HHS R35 GM136387NIGMS NIH HHS R35 GM156386NIGMS NIH HHS T32 GM131963
6 · The paper itself

Abstract

Cholesterol homeostasis in mammalian cells relies on the interaction between two endoplasmic reticulum (ER) sterol-sensing membrane proteins, Scap and Insig. Their interaction regulates activation of transcription factors called sterol regulatory element-binding proteins (SREBPs) that control genes for cholesterol biosynthesis and uptake. Previous studies suggested a model where cholesterol sensing by Scap involves communication across the ER membrane between two functional domains, a cholesterol-binding domain on the luminal side and a COPII-binding domain on the cytosolic side. When ER cholesterol is low, Scap binds COPII adapter proteins to facilitate ER-to-Golgi transport and proteolytic activation of SREBPs. When ER cholesterol is above a threshold concentration, this transport is blocked, a process that requires Insigs. However, the precise molecular mechanisms by which cholesterol and Insigs control the conformations of Scap remain unknown. Here, we elucidate the 3.2 Å cryo-EM structure of a Scap/Insig complex in the presence of saturating amounts of cholesterol. Structure-guided mutagenesis of the Scap/Insig interface indicates that Scap's transmembrane helix 7 (TM7) plays a critical role in transducing conformational changes between the luminal and cytosolic sides of the ER membrane to control Scap/SREBP transport from ER to Golgi. An intramembrane cholesterol bound at the Scap/Insig interface competes with the intramolecular interaction of Scap's TM7 at this interface to modulate cholesterol sensing. These results further advance our understanding of how Scap senses cholesterol and provides additional targets for controlling cholesterol and lipid synthesis in the context of metabolic diseases and even some cancers.

Indexed as

CholesterolIntracellular Signaling Peptides and ProteinsMembrane ProteinsSterol Regulatory Element Binding ProteinsCryoelectron MicroscopyEndoplasmic ReticulumGolgi ApparatusHumansProtein BindingCholesterolINSIG1 protein, humanIntracellular Signaling Peptides and ProteinsMembrane ProteinsSREBP cleavage-activating proteinSterol Regulatory Element Binding Proteinscholesterollipid metabolismScapSREBP

Identifiers

PMID41474747
PMCPMC12773782

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.