Endosomal/lysosomal proton channel TMEM175 (TMEM175) is a 504-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q9BSA9.
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The mean pLDDT of this model is 81.8 (confident overall). pLDDT is AlphaFold's per-residue confidence score from 0 to 100. In MolViewer, choose the B-factor color scheme to color the model by pLDDT, because AlphaFold stores it in the B-factor column.
| pLDDT band | Meaning | Share of residues |
|---|---|---|
| Above 90 | Very high: backbone and side chains are usually accurate | 45% |
| 70 to 90 | Confident: backbone generally right | 37% |
| 50 to 70 | Low: treat with caution | 7% |
| Below 50 | Very low: often disordered regions | 11% |
What pLDDT means and how to read it
Proton-activated proton channel that catalyzes proton efflux from endosomes and lysosomes to maintain a steady-state pH (PubMed:35333573, PubMed:35750034, PubMed:37390818). Activated at low pH (under pH 4.6) by luminal side protons: selectively mediates lysosomal proton release from lysosomes, eliciting a proton leak that balances V-ATPase activity to maintain pH homeostasis (PubMed:35750034). Regulation of lumenal pH stability is required for autophagosome-lysosome fusion (PubMed:26317472, PubMed:32267231). Also acts as a potassium channel at higher pH, regulating potassium conductance in endosomes and lysosomes (PubMed:26317472, PubMed:28723891, PubMed:32228865, PubMed:32267231,…
Homodimer (PubMed:28723891, PubMed:32228865, PubMed:35608336). Interacts with AKT (AKT1, AKT2 or AKT3); leading to formation of the lysoK(GF) complex, which activates the channel (PubMed:33505021). Interacts with LAMP1; inhibiting the proton channel activity of TMEM175 (PubMed:37390818). Interacts with LAMP2; inhibiting the proton channel activity of TMEM175 (PubMed:37390818)
Endosome membrane, Lysosome membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 7UNL | EM | 2.45 Å | A/B=1-504 |
| 7UNM | EM | 2.61 Å | A/B=1-504 |
| 6WC9 | EM | 2.64 Å | A/B=1-504 |
| 8DHM | EM | 2.73 Å | A/B=1-504 |
| 9VSQ | EM | 2.74 Å | A/B=1-504 |
| 9VSR | EM | 2.92 Å | A/B=1-504 |
| 6WCA | EM | 3.03 Å | A/B=1-504 |
| 6WCB | EM | 3.17 Å | A/B=1-504 |
| 6W8N | EM | 3.2 Å | A/B=1-504 |
| 6WCC | EM | 3.24 Å | A/B=1-504 |
| 6W8O | EM | 3.4 Å | A/B=1-504 |
| 8FY5 | EM | 3.4 Å | A/B=1-504 |
| 8FYF | EM | 3.4 Å | A/B=1-504 |
| 9VSP | EM | 3.4 Å | A/B=1-504 |
| 8VIC | EM | 3.48 Å | A/B=1-504 |
| 7LF6 | EM | 3.5 Å | A/B=1-504 |
| 8VIE | EM | 3.52 Å | A/B=1-504 |
| 6W8P | EM | 3.6 Å | A/B=1-504 |
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