+ Open data
Open data
- Basic information
Basic information
| Entry |  | ||||||||||||
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| Title | Cryo-EM structure of human Spns1 | ||||||||||||
|  Map data | |||||||||||||
|  Sample | 
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|  Keywords | lysosome / major facilitator superfamily / lysophospholipid transporter / lysophosphatidylcholine / MEMBRANE PROTEIN | ||||||||||||
| Function / homology |  Function and homology information lysophospholipid transport / regulation of lysosomal lumen pH / phospholipid efflux / transmembrane transporter activity / mitochondrial inner membrane / lysosomal membrane / membrane Similarity search - Function | ||||||||||||
| Biological species |  Homo sapiens (human) | ||||||||||||
| Method | single particle reconstruction / cryo EM / Resolution: 3.49 Å | ||||||||||||
|  Authors | Chen H / Li X | ||||||||||||
| Funding support |  United States, 3 items 
 | ||||||||||||
|  Citation |  Journal: Proc Natl Acad Sci U S A / Year: 2025 Title: Molecular basis of Spns1-mediated lysophospholipid transport from the lysosome. Authors: Hongwen Chen / Hoa T T Ha / Nadia Elghobashi-Meinhardt / Nhung A Le / Philip Schmiege / Long N Nguyen / Xiaochun Li /      Abstract: Spns1 mediates the rate-limiting efflux of lysophospholipids from the lysosome to the cytosol. Deficiency of Spns1 is associated with embryonic senescence, as well as liver and skeletal muscle ...Spns1 mediates the rate-limiting efflux of lysophospholipids from the lysosome to the cytosol. Deficiency of Spns1 is associated with embryonic senescence, as well as liver and skeletal muscle atrophy in animal models. However, the mechanisms by which Spns1 transports lysophospholipid and proton sensing remain unclear. Here, we present a cryogenic electron microscopy structure of human Spns1 in lysophosphatidylcholine (LPC)-bound lumen-facing conformation. Notably, LPC snugly binds within the luminal-open cavity, where the molecular dynamics simulations reveal that LPC presents a propensity to enter between transmembrane-helices (TM) 5 and 8. Structural comparisons and cell-based transport assays uncover several pivotal residues at TM 5/8 that orchestrate the transport cycle, which are unique to Spns1. Furthermore, we identify a five-residue network that is crucial for proton-sensing by Spns1. Transference of these network residues to Spns2, a sphingosine-1-phosphate uniporter, causes the chimeric Spns2 to be low pH dependent. Our results reveal molecular insights into lysosomal LPC transport and the proton-sensing mechanism by Spns1. | ||||||||||||
| History | 
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- Structure visualization
Structure visualization
| Supplemental images | 
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- Downloads & links
Downloads & links
-EMDB archive
| Map data |  emd_44741.map.gz | 97.1 MB |  EMDB map data format | |
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| Header (meta data) |  emd-44741-v30.xml  emd-44741.xml | 15.2 KB 15.2 KB | Display Display |  EMDB header | 
| FSC (resolution estimation) |  emd_44741_fsc.xml | 9.9 KB | Display |  FSC data file | 
| Images |  emd_44741.png | 37.5 KB | ||
| Filedesc metadata |  emd-44741.cif.gz | 5.2 KB | ||
| Others |  emd_44741_half_map_1.map.gz  emd_44741_half_map_2.map.gz | 95.8 MB 95.8 MB | ||
| Archive directory |  http://ftp.pdbj.org/pub/emdb/structures/EMD-44741  ftp://ftp.pdbj.org/pub/emdb/structures/EMD-44741 | HTTPS FTP | 
-Validation report
| Summary document |  emd_44741_validation.pdf.gz | 772.6 KB | Display |  EMDB validaton report | 
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| Full document |  emd_44741_full_validation.pdf.gz | 772.2 KB | Display | |
| Data in XML |  emd_44741_validation.xml.gz | 17.9 KB | Display | |
| Data in CIF |  emd_44741_validation.cif.gz | 22.7 KB | Display | |
| Arichive directory |  https://ftp.pdbj.org/pub/emdb/validation_reports/EMD-44741  ftp://ftp.pdbj.org/pub/emdb/validation_reports/EMD-44741 | HTTPS FTP | 
-Related structure data
| Related structure data |  9boiC C: citing same article ( | 
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| Similar structure data | Similarity search - Function & homology  F&H Search | 
- Links
Links
| EMDB pages |  EMDB (EBI/PDBe) /  EMDataResource | 
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| Related items in Molecule of the Month | 
- Map
Map
| File |  Download / File: emd_44741.map.gz / Format: CCP4 / Size: 103 MB / Type: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES) | ||||||||||||||||||||||||||||||||||||
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| Projections & slices | Image control
 
 Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
| Voxel size | X=Y=Z: 0.83 Å | ||||||||||||||||||||||||||||||||||||
| Density | 
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| Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
| Details | EMDB XML: 
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-Supplemental data
-Half map: #2
| File | emd_44741_half_map_1.map | ||||||||||||
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| Projections & Slices | 
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| Density Histograms | 
-Half map: #1
| File | emd_44741_half_map_2.map | ||||||||||||
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| Projections & Slices | 
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| Density Histograms | 
- Sample components
Sample components
-Entire : human Spns1 purified in the absence of extra LPC addition
| Entire | Name: human Spns1 purified in the absence of extra LPC addition | 
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| Components | 
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-Supramolecule #1: human Spns1 purified in the absence of extra LPC addition
| Supramolecule | Name: human Spns1 purified in the absence of extra LPC addition type: organelle_or_cellular_component / ID: 1 / Parent: 0 / Macromolecule list: all | 
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| Source (natural) | Organism:  Homo sapiens (human) | 
-Macromolecule #1: Protein spinster homolog 1, Spns1
| Macromolecule | Name: Protein spinster homolog 1, Spns1 / type: protein_or_peptide / ID: 1 / Enantiomer: LEVO | 
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| Source (natural) | Organism:  Homo sapiens (human) | 
| Recombinant expression | Organism:  Homo sapiens (human) | 
| Sequence | String: GRSALIVAVL CYINLLNYMD RFTVAGVLPD IEQFFNIGDS SSGLIQTVFI SSYMVLAPVF GYLGDRYNRK YLMCGGIAFW SLVTLGSSFI PGEHFWLLLL TRGLVGVGEA SYSTIAPTLI ADLFVADQRS RMLSIFYFAI PVGSGLGYIA GSKVKDMAGD WHWALRVTPG  ...String: GRSALIVAVL CYINLLNYMD RFTVAGVLPD IEQFFNIGDS SSGLIQTVFI SSYMVLAPVF GYLGDRYNRK YLMCGGIAFW SLVTLGSSFI PGEHFWLLLL TRGLVGVGEA SYSTIAPTLI ADLFVADQRS RMLSIFYFAI PVGSGLGYIA GSKVKDMAGD WHWALRVTPG LGVVAVLLLF LVVREPPRGA VERHSDLPPL NPTSWWADLR ALARNPSFVL SSLGFTAVAF VTGSLALWAP AFLLRSRVVL GETPPCLPGD SCSSSDSLIF GLITCLTGVL GVGLGVEISR RLRHSNPRAD PLVCATGLLG SAPFLFLSLA CARGSIVATY IFIFIGETLL SMNWAIVADI LLYVVIPTRR STAEAFQIVL SHLLGDAGSP YLIGLISDRL RRNWPPSFLS EFRALQFSLM LCAFVGALGG AAFLGTAIFI EADRRRAQLH VQGLLHEAGS TDDRIVVPQR GRSTRVPVAS VLI UniProtKB: Protein spinster homolog 1 | 
-Experimental details
-Structure determination
| Method | cryo EM | 
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|  Processing | single particle reconstruction | 
| Aggregation state | particle | 
- Sample preparation
Sample preparation
| Concentration | 15 mg/mL | ||||||||||||
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| Buffer | pH: 5.5 Component: 
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| Grid | Model: Quantifoil R1.2/1.3 / Material: GOLD / Mesh: 400 / Support film - Material: CARBON / Support film - topology: HOLEY / Pretreatment - Type: GLOW DISCHARGE | ||||||||||||
| Vitrification | Cryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 293 K / Instrument: FEI VITROBOT MARK IV | 
- Electron microscopy
Electron microscopy
| Microscope | FEI TITAN KRIOS | 
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| Image recording | Film or detector model: GATAN K3 (6k x 4k) / Average electron dose: 60.0 e/Å2 | 
| Electron beam | Acceleration voltage: 300 kV / Electron source:  FIELD EMISSION GUN | 
| Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 2.0 µm / Nominal defocus min: 1.0 µm | 
| Experimental equipment |  Model: Titan Krios / Image courtesy: FEI Company | 
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