9DSM
Cryo-EM structure of SSNA-1(R18E/R20E/Q98E) filaments
Summary for 9DSM
| Entry DOI | 10.2210/pdb9dsm/pdb |
| EMDB information | 47147 |
| Descriptor | Sjogren's Syndrome Nuclear Autoantigen (1 entity in total) |
| Functional Keywords | ssna1, dip13, na14, microtubules, centriole, centrosome, mitotic spindle, cytoskeleton, coiled-coil, cell cycle |
| Biological source | Caenorhabditis elegans |
| Total number of polymer chains | 32 |
| Total formula weight | 469320.93 |
| Authors | |
| Primary citation | Agostini, L.,Pfister, J.A.,Basnet, N.,Ding, J.,Zhang, R.,Biertumpfel, C.,O'Connell, K.F.,Mizuno, N. Structural insights into SSNA1 self-assembly and its microtubule binding for centriole maintenance. Nat Commun, 16:7512-7512, 2025 Cited by PubMed Abstract: SSNA1 is a fibrillar protein involved in dynamic microtubule remodeling, including nucleation, co-polymerization, and microtubule branching. The underlying molecular mechanism has remained unclear due to a lack of structural information. Here, we determine the cryo-EM structure of C.elegans SSNA-1 at 4.55-Å resolution and evaluate its role in embryonic development. We find that SSNA-1 forms an anti-parallel coiled-coil, with self-assembly facilitated by an overhang of 16 C-terminal residues that form a triple-stranded helical junction. The microtubule-binding region is within the triple-stranded junction, suggesting that self-assembly of SSNA-1 creates hubs for effective microtubule interaction. Genetical analysis elucidates that SSNA-1 deletion significantly reduces embryonic viability, and causes multipolar spindles during cell division. Interestingly, impairing SSNA-1 self-assembly has a comparable effect on embryonic viability as the knockout strain. Our study provides molecular insights into SSNA-1's self-assembly and its role in microtubule binding and cell division regulation through centriole stability. PubMed: 40804232DOI: 10.1038/s41467-025-62696-9 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (4.55 Å) |
Structure validation
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