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97  structures 1419  species 0  interactions 4338  sequences 66  architectures

Family: HORMA (PF02301)

Summary: HORMA domain

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This is the Wikipedia entry entitled "HORMA domain". More...

HORMA domain Edit Wikipedia article

HORMA domain
PDB 1go4 EBI.jpg
crystal structure of mad1-mad2 reveals a conserved mad2 binding motif in mad1 and cdc20.
Symbol HORMA
Pfam PF02301
InterPro IPR003511
SCOP 1duj

In molecular biology, the HORMA domain (named after the Hop1p, Rev7p and MAD2 proteins) is a protein domain that has been suggested to recognise chromatin states resulting from DNA adducts, double stranded breaks or non-attachment to the spindle and act as an adaptor that recruits other proteins. Hop1 is a meiosis-specific protein, Rev7 is required for DNA damage induced mutagenesis, and MAD2 is a spindle checkpoint protein which prevents progression of the cell cycle upon detection of a defect in mitotic spindle integrity.[1][2]


Humans proteins containing this domain include:


External links

This article incorporates text from the public domain Pfam and InterPro IPR003511

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.

HORMA domain Provide feedback

The HORMA (for Hop1p, Rev7p and MAD2) domain has been suggested to recognise chromatin states that result from DNA adducts, double stranded breaks or non-attachment to the spindle and acts as an adaptor that recruits other proteins. MAD2 is a spindle checkpoint protein which prevents progression of the cell cycle upon detection of a defect in mitotic spindle integrity.

Literature references

  1. He X, Patterson TE, Sazer S; , Proc Natl Acad Sci U S A 1997;94:7965-7970.: The Schizosaccharomyces pombe spindle checkpoint protein mad2p blocks anaphase and genetically interacts with the anaphase-promoting complex. PUBMED:9223296 EPMC:9223296

  2. Aravind L, Koonin EV; , Trends Biochem Sci 1998;23:284-286.: The HORMA domain: a common structural denominator in mitotic checkpoints, chromosome synapsis and DNA repair. PUBMED:9757827 EPMC:9757827

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR003511

The HORMA domain (for HOP1, REV7 and MAD2) is an about 180-240 amino acids region containing several conserved motifs. Whereas the MAD2 and the REV7 proteins are almost entirely made up of HORMA domains, HOP1 contains a HORMA domain in its N-terminal region and a Zn-finger domain, whose general arrangement of metal-chelating residues is similar to that of the PHD finger, in the C-terminal region. The HORMA domain is found in proteins showing a direct association with chromatin of all crown group eukaryotes. It has been suggested that the HORMA domain recognises chromatin states that result from DNA adducts, double-stranded breaks or non-attachment to the spindle and acts as an adaptor that recruits other proteins involved in repair [ PUBMED:9757827 ].

Secondary structure prediction suggests that the HORMA domain is globular and could potentially form a complex beta-sheet(s) with associated alpha-helices [ PUBMED:9757827 ].

Some proteins known to contain a HORMA domain are listed below:

  • Eukaryotic HOP1, a conserved protein that is involved in meiotic- synaptonemal-complex assembly.
  • Eukaryotic mitotic-arrest-deficient 2 protein (MAD2), a key component of the mitotic-spindle-assembly checkpoint.
  • Eukaryotic REV7, a subunit of the DNA polymerase zeta that is involved in translesion, template-independent DNA synthesis.

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 Mad2 (CL0651), which has the following description:

The clan contains the following 5 members:

ATG101 ATG13 bacHORMA_2 HORMA p31comet


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

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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.

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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: [2]
Previous IDs: MAD2;
Type: Domain
Sequence Ontology: SO:0000417
Author: Bateman A , Mian N
Number in seed: 115
Number in full: 4338
Average length of the domain: 173.20 aa
Average identity of full alignment: 20 %
Average coverage of the sequence by the domain: 52.47 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 57096847 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 21.4 21.4
Trusted cut-off 21.4 21.4
Noise cut-off 21.3 21.3
Model length: 218
Family (HMM) version: 20
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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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 HORMA domain has been found. There are 97 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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