Major Sperm Protein (MSP)

As its name suggests, the Major Sperm Protein is the most abundant protein in a nematode sperm, comprising about 15% of the total cell protein. MSP plays an essential role in nematode sperm motility. Within the sperm's pseudopod, individual MSP molecules form long chains, which further associate with each other to form a dense network of bundles. The constant assembly of this network at the leading edge of the pseudopod and disassembly at the back end is what moves the pseudopod membrane, allowing the cell to crawl forward. You can watch a video of this pseudopod treadmilling in action.

Although MSP is abundant in the sperm of all nematode species, it has not been found in any other organism. This underscores just how unusual nematode sperm motility is. However, we are beginning to find proteins in other organisms--including humans--whose amino acid sequence is similar to MSP. Perhaps these proteins perform some function similar to the role MSP plays in moving nematode sperm. We hope to find the answer soon.

Take a look at our MSP Molecular Displayer. You can rotate and zoom in on an MSP molecule, or even change its colors and modeling scheme to show different features, all from within the web page. You need a browser plugin, called Chime, to use the displayer, and it does not work on all browsers or versions, so take a look at the instructions first.

Perform a Literature Search for References on MSP

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