Glad to see the work of my PhD on the manchette microtubule now out in @embojournal.org: doi.org/10.1038/s443...
Super happy to see our paper on the 🔗LINC lattice in mammalian sperm in its final form: doi.org/10.1073/pnas....
Thanks to everyone involved @tzviyazbm.bsky.social, Svetlana Doroshev and Miguel Leung!
The manchette is a transient microtubule (MT)-based structure that is vital for the correct shaping of sperm during spermiogenesis. Throughout spermiogenesis, the manchette retains structural integrity for several days, raising the question of how its MTs are regulated. Here, using cryo-electron tomography of manchettes isolated from rat testes, we find that manchette MT ends are structurally diverse. We show that the MT-binding protein CLASP2 is present throughout the manchette and likely regulates both MT ends. Using cryo-electron microscopy single particle analysis and super-resolution microscopy, we reveal that SPACA9 and MNMIP1 (SH3D21) bind to the seam of manchette MTs from the luminal side. SPACA9 binds to both α- and β-tubulin of protofilament 1 but does not interact directly with protofilament 13, while MNMIP1 binds directly to protofilament 13. MNMIP1 further extends and threads through the MT lattice at the seam. Our study reveals a novel seam MT inner protein complex with a unique binding mode, providing a plausible explanation for MT regulation that maintains manchette integrity over an extended period.
We revealed SPACA9 and MNMIP1 forming a complex that bridges the seam of manchette microtubules in 8-nm intervals on the luminal side. Our data suggest that the complex may be involved in regulating manchette microtubules by stabilizing the microtubule seam.
The spermatid manchette is a transient microtubular structure critical for shaping sperm cells. In this study, we used cryo-ET and cryo-EM on isolated rat manchettes.
Thanks to Rui Zhang, Elizabeth Bromfield, Anna Akhmanova, Robin Hoogebeen, and Donna Schweizer for all the help. And thanks to my former group, Svetlana Doroshev, Sven Jonkers, @molly-gravett.bsky.social, @schowes.bsky.social, and especially @tzviyazbm.bsky.social for making this possible.
