9RPD

D. melanogaster Augmin TII N-clamp (GST-fusion) bound to a microtubule, well-defined subset of particles

Summary for 9RPD

• Entry DOI: 10.2210/pdb9rpd/pdb
• Related: 9RPD
• EMDB information: 52832 54160 54161 54174
• Descriptor: Augmin complex subunit dgt4, Augmin complex subunit dgt6, Augmin complex subunit msd5,Green fluorescent protein,Glutathione S-transferase class-mu 26 kDa isozyme, ... (5 entities in total)
• Functional Keywords: augmin, n-clamp, tii, microtubule, branching, nucleation, haus, haus augmin-like complex subunit, haus6, haus7, haus2, haus8, dgt6, msd5, dgt4, msd1, drosophila melanogaster, complex, ch domain, calponin homology domain, cell cycle, map, cell division
• Biological source: Drosophila melanogaster (fruit fly); More
• Total number of polymer chains: 9
• Total formula weight: 421490.98

Authors

Wuertz, M.,Vermeulen, B.J.A.,Tonon, G.,Pfeffer, S. (deposition date: 2025-06-24, release date: 2025-08-27, Last modification date: 2025-09-03)

Primary citation

Wurtz, M.,Tonon, G.,Vermeulen, B.J.A.,Zezlina, M.,Gao, Q.,Neuner, A.,Seidl, A.,Konig, M.,Harkenthal, M.,Eustermann, S.,Erhardt, S.,Lolicato, F.,Schiebel, E.,Pfeffer, S.
Conserved function of the HAUS6 calponin homology domain in anchoring augmin for microtubule branching.
Nat Commun, 16:7845-7845, 2025

PubMed Abstract: Branching microtubule nucleation is a key mechanism for mitotic and meiotic spindle assembly and requires the hetero-octameric augmin complex. Augmin recruits the major microtubule nucleator, the γ-tubulin ring complex, to pre-existing microtubules to direct the formation of new microtubules in a defined orientation. Although recent structural work has provided key insights into the structural organization of augmin, molecular details of its interaction with microtubules remain elusive. Here, we identify the minimal conserved microtubule-binding unit of augmin across species and demonstrate that stable microtubule anchoring is predominantly mediated via the calponin homology (CH) domain in Dgt6/HAUS6. Comparative sequence and functional analyses in vitro and in vivo reveal a highly conserved functional role of the HAUS6 CH domain in microtubule binding. Using cryo-electron microscopy and molecular dynamics simulations in combination with AlphaFold structure predictions, we show that the D. melanogaster Dgt6/HAUS6 CH domain binds microtubules at the inter-protofilament groove between two adjacent β-tubulin subunits and thereby orients augmin on microtubules. Altogether, our findings reveal how augmin binds microtubules to pre-determine the branching angle during microtubule nucleation and facilitate the rapid assembly of complex microtubule networks.

PubMed: 40846850
DOI: 10.1038/s41467-025-63165-z

Experimental method

ELECTRON MICROSCOPY (4.9 Å)