6GQF

The structure of mouse AsterA (GramD1a) with 25-hydroxy cholesterol

• PDB DOI:  https://doi.org/10.2210/pdb6GQF/pdb

• Classification: LIPID TRANSPORT
• Organism(s): Mus musculus
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): No 
• Membrane Protein: Yes  OPM


• Deposited: 2018-06-07 Released: 2018-09-26 
• Deposition Author(s): Fairall, L., Gurnett, J.E., Vashi, D., Sandhu, J., Tontonoz, P., Schwabe, J.W.R.
• Funding Organization(s): Wellcome Trust, Royal Society

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.90 Å
• R-Value Free: 0.258 
• R-Value Work: 0.201 
• R-Value Observed: 0.204 

Literature

Aster Proteins Facilitate Nonvesicular Plasma Membrane to ER Cholesterol Transport in Mammalian Cells.

Sandhu, J., Li, S., Fairall, L., Pfisterer, S.G., Gurnett, J.E., Xiao, X., Weston, T.A., Vashi, D., Ferrari, A., Orozco, J.L., Hartman, C.L., Strugatsky, D., Lee, S.D., He, C., Hong, C., Jiang, H., Bentolila, L.A., Gatta, A.T., Levine, T.P., Ferng, A., Lee, R., Ford, D.A., Young, S.G., Ikonen, E., Schwabe, J.W.R., Tontonoz, P.

(2018) Cell 175: 514-529.e20

• PubMed: 30220461 
• DOI: https://doi.org/10.1016/j.cell.2018.08.033
• Primary Citation of Related Structures:  
  6GQF


• PubMed Abstract: 
  

The mechanisms underlying sterol transport in mammalian cells are poorly understood. In particular, how cholesterol internalized from HDL is made available to the cell for storage or modification is unknown. Here, we describe three ER-resident proteins (Aster-A, -B, -C) that bind cholesterol and facilitate its removal from the plasma membrane. The crystal structure of the central domain of Aster-A broadly resembles the sterol-binding fold of mammalian StARD proteins, but sequence differences in the Aster pocket result in a distinct mode of ligand binding. The Aster N-terminal GRAM domain binds phosphatidylserine and mediates Aster recruitment to plasma membrane-ER contact sites in response to cholesterol accumulation in the plasma membrane. Mice lacking Aster-B are deficient in adrenal cholesterol ester storage and steroidogenesis because of an inability to transport cholesterol from SR-BI to the ER. These findings identify a nonvesicular pathway for plasma membrane to ER sterol trafficking in mammals.

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Organizational Affiliation: 

Department of Pathology and Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA. Electronic address: [e-mail].

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Biological Assembly 2  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 2 assigned by authors.

Biological Assembly 3  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 3 assigned by authors.

Biological Assembly 4  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 4 assigned by authors.

Macromolecule Content

• Total Structure Weight: 105.82 kDa 
• Atom Count: 5,465 
• Modelled Residue Count: 666 
• Deposited Residue Count: 924 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
GRAM domain-containing protein 1A	A, B, C, D	231	Mus musculus	Mutation(s): 0  Gene Names: Gramd1a, D7Bwg0611e, Kiaa1533 Membrane Entity: Yes
UniProt
Find proteins for Q8VEF1 (Mus musculus) Explore Q8VEF1  Go to UniProtKB:  Q8VEF1

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
HC3	E [auth A], G [auth B], I [auth C], K [auth D]	25-HYDROXYCHOLESTEROL C27 H46 O2 INBGSXNNRGWLJU-ZHHJOTBYSA-N
GOL	F [auth A], H [auth B], J [auth C], L [auth D]	GLYCEROL C3 H8 O3 PEDCQBHIVMGVHV-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.90 Å
• R-Value Free: 0.258 
• R-Value Work: 0.201 
• R-Value Observed: 0.204 
• Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 52.435	α = 90
b = 121.012	β = 110.84
c = 71.907	γ = 90

Software Package:

Software Name	Purpose
PHENIX	refinement
xia2	data reduction
Aimless	data scaling
PHASER	phasing

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2018-09-26 
Deposition Author(s): Fairall, L., Gurnett, J.E., Vashi, D., Sandhu, J., Tontonoz, P., Schwabe, J.W.R.

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Funding Organization	Location	Grant Number
Wellcome Trust	United Kingdom	WT100237
Royal Society	United Kingdom	Wolfson Research Merit award

Revision History  

• Version 1.0: 2018-09-26
  Type: Initial release
  
• Version 1.1: 2018-10-17
  Changes: Data collection, Database references, Structure summary