9I2B
SPIN90-Arp2/3 nucleated bidirectional actin filaments
Summary for 9I2B
| Entry DOI | 10.2210/pdb9i2b/pdb |
| EMDB information | 52580 |
| Descriptor | Actin-related protein 2, Actin-related protein 3, ADENOSINE-5'-DIPHOSPHATE, ... (12 entities in total) |
| Functional Keywords | cytoskeleton, branched actin network, cytosolic protein |
| Biological source | Homo sapiens (human) More |
| Total number of polymer chains | 24 |
| Total formula weight | 781829.39 |
| Authors | Liu, T.,Moores, C.A. (deposition date: 2025-01-20, release date: 2025-09-03, Last modification date: 2025-09-24) |
| Primary citation | Liu, T.,Cao, L.,Mladenov, M.,Romet-Lemonne, G.,Way, M.,Moores, C.A. Arp2/3-mediated bidirectional actin assembly by SPIN90 dimers. Nat.Struct.Mol.Biol., 2025 Cited by PubMed Abstract: Branched actin networks nucleated by the Arp2/3 complex have critical roles in various cellular processes, from cell migration to intracellular transport. However, when activated by WISH/DIP/SPIN90-family proteins, Arp2/3 nucleates linear actin filaments. Here we found that human SPIN90 is a dimer that can nucleate bidirectional actin filaments. To understand the basis for this, we determined a 3-Å-resolution structure of human SPIN90-Arp2/3 complex nucleating actin filaments. Our structure shows that SPIN90 dimerizes through a three-helix bundle and interacts with two Arp2/3 complexes. Each SPIN90 molecule binds both Arp2/3 complexes to promote their activation. Our analysis demonstrates that single-filament nucleation by Arp2/3 is mechanistically more like branch formation than previously appreciated. The dimerization domain in SPIN90 orthologs is conserved in metazoans, suggesting that this mode of bidirectional nucleation is a common strategy to generate antiparallel actin filaments. PubMed: 40954369DOI: 10.1038/s41594-025-01665-8 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3 Å) |
Structure validation
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