Related Experiment Video

Updated: Jun 14, 2026

A Seminiferous Tubule Squash Technique for the Cytological Analysis of Spermatogenesis Using the Mouse Model
09:40

A Seminiferous Tubule Squash Technique for the Cytological Analysis of Spermatogenesis Using the Mouse Model

Published on: February 6, 2018

SPACA9 and MNMIP1 bridge the seam of spermatid manchette microtubules

Jo H Judernatz1,2, Svetlana Doroshev1, Robin A Hoogebeen3

  • 1Bijvoet Centre for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.

The EMBO Journal
|June 12, 2026
PubMed

Insights

The manchette, a sperm-shaping structure, maintains integrity via microtubule (MT) regulation. Novel proteins SPACA9 and MNMIP1 bind MT seams, explaining sustained manchette stability during spermiogenesis.

Area of Science:

  • Cell Biology
  • Structural Biology
  • Reproductive Biology

Background:

  • The manchette is a transient microtubule (MT)-based structure essential for sperm shaping during spermiogenesis.
  • Maintaining manchette integrity for several days presents a question regarding its MT regulation.

Purpose of the Study:

  • To investigate the molecular mechanisms regulating microtubule (MT) stability within the manchette during spermiogenesis.
  • To identify proteins involved in maintaining the structural integrity of the manchette.

Main Methods:

  • Cryo-electron tomography of isolated rat testis manchettes.
  • Cryo-electron microscopy single particle analysis.
  • Super-resolution microscopy.

Main Results:

  • Manchette MT ends exhibit structural diversity.
  • The MT-binding protein CLASP2 is present throughout the manchette, potentially regulating MT ends.
  • SPACA9 and MNMIP1 (SH3D21) bind to the manchette MT seam from the luminal side.
  • SPACA9 interacts with α- and β-tubulin at protofilament 1, while MNMIP1 binds directly to protofilament 13 and extends through the MT lattice.

Conclusions:

  • A novel inner protein complex at the MT seam, formed by SPACA9 and MNMIP1, provides a unique binding mode.
  • This complex offers a plausible explanation for the sustained regulation and stability of manchette MTs during spermiogenesis.

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