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50  structures 1493  species 0  interactions 9387  sequences 333  architectures

Family: Motile_Sperm (PF00635)

Summary: MSP (Major sperm protein) domain

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "Major sperm protein". More...

Major sperm protein Edit Wikipedia article

The Major Sperm Protein, commonly abbrieviated to MSP, is the most abundant protein in nematode sperm, making up about 15% of the total protein in the sperm cell. It is responsible for the cell's motility.

The MSP molecules are part of the cell cytoskeleton. They are built up into a set of long chains organised into bundles at the front of the cell, and are disassembled at the back. This pushes the cell forward in a process called treadmilling.

Although there are similar amino acid sequences in other organisms, MCP appears to be unique to the sperm of nematodes.



This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

MSP (Major sperm protein) domain Provide feedback

Major sperm proteins are involved in sperm motility. These proteins oligomerise to form filaments. This family contains many other proteins.

Literature references

  1. Bullock TL, Roberts TM, Stewart M; , J Mol Biol 1996;263:284-296.: 2.5 A resolution crystal structure of the motile major sperm protein (MSP) of Ascaris suum. PUBMED:8913307 EPMC:8913307

  2. King KL, Stewart M, Roberts TM, Seavy M; , J Cell Sci 1992;101:847-857.: Structure and macromolecular assembly of two isoforms of the major sperm protein (MSP) from the amoeboid sperm of the nematode, Ascaris suum. PUBMED:1527183 EPMC:1527183

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR000535

Nematode sperm are unusual amoeboid cells in which motility is not based on actin, but instead on the major sperm protein (MSP). MSP is a dimeric molecule that polymerises to form non-polar filaments constructed from two helical subfilaments that wind round one another. The filaments then assemble into larger macromolecular assemblies called fibre complexes. MSP is a small (~14kDa) basic protein typically encoded by a multigene family of up to 28 members [ PUBMED:8913307 , PUBMED:12051923 , PUBMED:9878374 , PUBMED:9641981 ]. An about 120-amino acid domain similar to MSP has been found in other proteins, including:

  • Animal Vesicle-Associated Membrane Protein-associated (VAMP-associated) protein family of 33kDa (VAP33). VAP33 is required for neurotransmitter release. It binds to the v-SNARE synaptobrevin/VAMP which is associated with vesicle fusion. VAP33 has a two-domain structure with its N terminus being highly homologous to MSP, whereas its C terminus is based on a putative alpha-helical coiled-coil combined with an extremely hydrophobic membrane-attachment region [ PUBMED:9920726 ].
  • Nicotiana plumbaginifolia VAP27, a VAP33 homologue. It interacts with the resistance protein Cf9 [ PUBMED:10733941 ].
  • Yeast inositol regulator SCS2, a VAP33 homologue. It is C-terminally anchored to the endoplasmic reticulum [ PUBMED:9537365 ].

The MSP polypeptide chain has an immunoglobulin-like fold based on a seven-stranded beta sandwich measuring approximately 15 A x 20 A x 45 A and having opposing three-stranded and four-stranded beta sheets [ PUBMED:8913307 ].

This entry represents the MSP domain.

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Pfam Clan

This family is a member of clan PapD-like (CL0556), which has the following description:

This superfamily is characterised by proteins in families involved in ciliary or flagellar function. The families may be acting as chaperones.

The clan contains the following 8 members:

ASH DUF1573 EcpB_C Motile_Sperm PapD-like PapD_N Peptidase_M60_C TMEM131_like_N


We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

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We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

Representative proteomes UniProt
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Representative proteomes UniProt

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We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

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You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...


This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Prosite
Previous IDs: MSP_domain;
Type: Domain
Sequence Ontology: SO:0000417
Author: Bateman A , Griffiths-Jones SR
Number in seed: 50
Number in full: 9387
Average length of the domain: 103.2 aa
Average identity of full alignment: 24 %
Average coverage of the sequence by the domain: 33.05 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 25.9 25.9
Trusted cut-off 25.9 25.9
Noise cut-off 25.8 25.8
Model length: 109
Family (HMM) version: 29
Download: download the raw HMM for this family

Species distribution

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Colour assignments

Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

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The tree shows the occurrence of this domain across different species. More...


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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Motile_Sperm domain has been found. There are 50 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
A0A044QK58 View 3D Structure Click here
A0A044QM59 View 3D Structure Click here
A0A044QXV7 View 3D Structure Click here
A0A044R1Z4 View 3D Structure Click here
A0A044R930 View 3D Structure Click here
A0A044RIB1 View 3D Structure Click here
A0A044RQN1 View 3D Structure Click here
A0A044S6N4 View 3D Structure Click here
A0A044SCS4 View 3D Structure Click here
A0A044SJC4 View 3D Structure Click here
A0A044SSJ4 View 3D Structure Click here
A0A044SSY5 View 3D Structure Click here
A0A044THM7 View 3D Structure Click here
A0A044U4H3 View 3D Structure Click here
A0A044U965 View 3D Structure Click here
A0A044UGH9 View 3D Structure Click here
A0A044UI93 View 3D Structure Click here
A0A044UJU5 View 3D Structure Click here
A0A044UNX6 View 3D Structure Click here
A0A044UPD8 View 3D Structure Click here
A0A044V0L0 View 3D Structure Click here
A0A044V8L4 View 3D Structure Click here
A0A044V9P6 View 3D Structure Click here
A0A044VAC4 View 3D Structure Click here
A0A044VIK6 View 3D Structure Click here
A0A077YXN6 View 3D Structure Click here
A0A077YYW0 View 3D Structure Click here
A0A077YZC9 View 3D Structure Click here
A0A077YZJ4 View 3D Structure Click here
A0A077YZP2 View 3D Structure Click here
A0A077Z0D6 View 3D Structure Click here
A0A077Z0Z2 View 3D Structure Click here
A0A077Z265 View 3D Structure Click here
A0A077Z4C1 View 3D Structure Click here
A0A077Z4T5 View 3D Structure Click here
A0A077Z4X5 View 3D Structure Click here
A0A077Z5I3 View 3D Structure Click here
A0A077Z796 View 3D Structure Click here
A0A077Z7M4 View 3D Structure Click here
A0A077Z829 View 3D Structure Click here