The motile major sperm protein (MSP) of Ascaris suum forms filaments constructed from two helical subfilaments

Related Experiment Video

Updated: Aug 17, 2026

Microdissection of Black Widow Spider Silk-producing Glands
09:47

Microdissection of Black Widow Spider Silk-producing Glands

Published on: January 11, 2011

M Stewart1, K L King, T M Roberts

  • 1M.R.C. Laboratory of Molecular Biology, Cambridge, U.K.

Journal of Molecular Biology
|October 14, 1994
PubMed

Insights

Nematode sperm motility relies on major sperm protein (MSP) filaments. These filaments assemble from helical subfilaments, revealing how MSP structures enable amoeboid movement.

Area of Science:

  • Cell Biology
  • Biophysics
  • Structural Biology

Background:

  • Amoeboid motility in nematode sperm is driven by cytoskeletal filaments.
  • Major sperm protein (MSP) is the primary component of these filaments.

Purpose of the Study:

  • To elucidate the structural organization of MSP filaments.
  • To understand the molecular mechanisms underlying MSP filament assembly and its role in motility.

Main Methods:

  • Electron microscopy was employed to visualize MSP filament structure.
  • Advanced image processing techniques were utilized for detailed structural analysis.

Main Results:

  • MSP filaments are composed of two subfilament strands.
  • Each subfilament is a left-handed helix (9 nm pitch) that coils into a right-handed helix (22.5 nm pitch) to form the filament.
  • This helical structure influences protein-protein interactions, enabling filament bundling into larger structures like macrofibers and fiber bundles.

Conclusions:

  • The helical structure of MSP filaments is crucial for their assembly and function.
  • Filament bundling, alongside vectorial assembly, is essential for nematode sperm amoeboid motility.
  • The findings provide insights into the supramolecular organization of MSP and its role in cellular mechanics.

More Related Videos

Myosin-Specific Adaptations of In vitro Fluorescence Microscopy-Based Motility Assays08:57

Myosin-Specific Adaptations of In vitro Fluorescence Microscopy-Based Motility Assays

Published on: February 4, 2021

Probing Myosin Ensemble Mechanics in Actin Filament Bundles Using Optical Tweezers06:53

Probing Myosin Ensemble Mechanics in Actin Filament Bundles Using Optical Tweezers

Published on: May 4, 2022

Related Concept Videos

Assembly of Cytoskeletal Filaments01:18

Assembly of Cytoskeletal Filaments

Cytoskeletal filaments are polymeric forms of smaller protein subunits. However, individual cytoskeletal filaments may easily disassemble or associate with other similar filaments to form rigid structures. Microfilaments, made of actin monomers, rely on actin-binding proteins to form bundles and create networks of individual actin filaments. Microtubules rely on microtubule-associated proteins (MAPs) to form sturdy cylindrical structures. However, the proteins involved in forming complex...
Generation of Straight or Branched Actin Filaments01:14

Generation of Straight or Branched Actin Filaments

The straight or branched structure formation of actin filaments is controlled by nucleating proteins such as the formins and Arp2/3 complex. Formin-mediated assembly results in straight filaments, whereas Arp2/3 protein complex-mediated assembly results in branched actin filaments.
Arp2/3 Complex
Arp2/3 complex is a seven-subunit complex consisting of two proteins similar to actin- Arp2 and Arp3, and five other subunits that help keep Arp2 and Arp3 inactive. When required, the complex is...
Overview of Myosin Structure and Function01:15

Overview of Myosin Structure and Function

Myosins are a family of molecular motor proteins, first identified in the skeletal muscles, where they are responsible for muscle contraction. Along with their role in muscle contraction, these proteins also play a role in the intracellular transport of molecules and vesicles. There are twenty-four classes of myosins based on their domain sequence and organization. Of the twenty-four, six classes (Myosin I, Myosin II, Myosin V, Myosin VI, Myosin VII, and Myosin X)  have been well characterized.
Microtubule Associated Motor Proteins01:32

Microtubule Associated Motor Proteins

Eukaryotic cells have different motor proteins for transporting various cargo within the cell. These motor proteins differ based on the filament they associate with, the direction they move within the cell, and the type of cargo they transport. Motor proteins that associate with microtubules are known as microtubule-associated motor proteins. There are two families of microtubule-associated motor proteins —Kinesins and Dyneins. Both these proteins assist in the transport of cellular cargos...
Microtubules in Cell Motility01:24

Microtubules in Cell Motility

Microtubules are thick hollow cylindrical proteins that help form the cytoskeleton. Microtubules have varied roles in the cell. These filaments help form cellular appendages like cilia and flagella, which are responsible for locomotion. The cilia arise from basal bodies, separated from the main body by a membrane-like structure forming the transition zone. This zone is the gate for the entry of lipids and proteins, creating a unique composition of lipids and proteins in the ciliary membrane and...
The Mitotic Spindle02:27

The Mitotic Spindle

The mitotic spindle—or spindle apparatus—is a eukaryotic, cytoskeletal structure made up of long protein fibers called microtubules. Formed during cell division, the spindle separates sister chromatids and moves them to opposite ends of a parental cell, where the now individual chromosomes are distributed to two daughter cell nuclei.
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures bipolar mitotic...