SPACA9 and MNMIP1 bridge the seam of spermatid manchette microtubules - The EMBO Journal

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.

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PNAS

Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...

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33 million euro investment for national electron microscope facility EMPower

A major new national facility for electron microscopy, called EMPower, has been awarded to a consortium of Dutch universities and medical centers. EMPower aims to pave the way for major discoveries im...

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#hiring #researchassociate #structuralbiology #proteinsciences #cryoem #biochemistry #biophysics #dnarepair #drugdiscovery | Stanislau Yatskevich

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Cryo-EM single-particle analysis expanding towards increasingly native samples

Cryo-EM single-particle analysis has revolutionized structural biology by allowing high-resolution analysis of large molecular assemblies that are not amenable to crystallography or NMR. Combination of this technology with innovative sample-preparation protocols further expands the range of potential targets.

journals.iucr.org

SUN5 forms a regular protein lattice reinforcing the sperm head-tail junction

Linker of nucleo- and cytoskeleton (LINC) complexes reside in the nuclear envelope, the double-membrane surrounding the nucleus, where they establish a physical bridge between nucleus and cytoplasm. L...

biorxiv.org