9Q1F
Choanoflagellate Salpingoeca macrocollata STING
Summary for 9Q1F
| Entry DOI | 10.2210/pdb9q1f/pdb |
| Descriptor | Endolysin,Stimulator of interferon genes, cGAMP (3 entities in total) |
| Functional Keywords | innate immunity, cyclic dinucleotide signaling, stimulator of interferon genes, cgas-sting, immune system |
| Biological source | Salpingoeca macrocollata More |
| Total number of polymer chains | 2 |
| Total formula weight | 84996.02 |
| Authors | |
| Primary citation | Li, Y.,Toyoda, H.C.,Fernandez, S.G.,Tiwari, B.,McNairy, C.,Woznica, A.,Kranzusch, P.J. A choanoflagellate cGLR-STING pathway reveals evolutionary links between bacterial and animal immunity. Biorxiv, 2025 Cited by PubMed Abstract: Animal innate immunity evolved from ancient pathways in bacterial anti-phage defense. How bacterial immune components were first acquired and adapted within eukaryotic cells remains poorly understood. Here we identify a complete cGLR-STING signaling axis in choanoflagellates, the closest living relatives of animals, that exhibits a mosaic of features from both bacterial and animal immunity. Comparative genomics reveals choanoflagellate and genes organized in operon-like arrangements reminiscent of bacterial defense loci. Reconstitution of choanoflagellate cGLR-STING signaling demonstrates that activation occurs through the conserved nucleotide immune signal 2'3'-cGAMP. Structural analysis of a choanoflagellate STING-2'3'-cGAMP complex explains how retention of bacterial-like features in early eukaryotic proteins shapes ligand specificity and receptor activation. We analyze and evolution in unicellular eukaryotes and identify further STING homologs in choanoflagellates and fungi that support additional independent acquisition events. Our results reveal molecular fossils that bridge bacterial and animal immunity and illuminate early eukaryotic immune system evolution. PubMed: 40950183DOI: 10.1101/2025.09.04.674280 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.65 Å) |
Structure validation
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