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We are deeply saddened by the passing of Amos Bairoch (1957–2025), the creator of PROSITE. We wish to dedicate our latest paper, published shortly before his death, to him. He will always be a source of inspiration to us.
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Amos Bairoch

PROSITE documentation PDOC51469
SUN domain profile


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PURL: https://purl.expasy.org/prosite/documentation/PDOC51469

Description

Sad1/UNC-84 (SUN)-domain proteins are inner nuclear membrane (INM) proteins that are part of bridging complexes linking cytoskeletal elements with the nucleoskeleton. Originaly identified based on an ~150-amino acid region of homology between the C terminus of the Schizosaccharomyces pombe Sad1 protein and the Caenorhabditis elegans UNC-84 protein, SUN proteins are present in the proteomes of most eucaryotes. In addition to the SUN domain, these proteins contain a transmembrane sequence and at least one coiled-coil domain and localize to the inner nuclear envelope. SUN proteins are anchored in the inner nuclear envelope by their transmembrane segment and oriented in the membrane such that the C-terminal SUN domain is located in the space between the inner and outer nuclear membrane. Here, the SUN domain can interact with the C-terminal tail of an outer nuclear envelope protein that binds to the cytoskeleton, including the centrosome [1,2,3].

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

  • Fission yeast spindle pole body-associated protein Sad1.
  • Yeast spindle pole body assembly component MPS3, essential for nuclear division and fusion.
  • Yeast uncharacterized protein SLP1.
  • Caenorhabditis nuclear migration and anchoring protein UNC-84.
  • Caenorhabditis SUN domain-containing protein 1 (sun-1), involved in centrosome attachment to the nucleus.
  • Mammalian sperm-associated antigen 4 protein (SPAG4), may assist the organization and assembly of outer dense fibers (ODFs), a specific structure of the sperm tail.
  • Mammalian sperm-associated antigen 4-like protein (SPAG4L).
  • Mammalian SUN1.
  • Mammalian SUN2.
  • Mammalian SUN3.

The profile we developed covers the entire SUN domain.

Last update:

November 2009 / First entry.

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Technical section

PROSITE method (with tools and information) covered by this documentation:

SUN, PS51469; SUN domain profile  (MATRIX)


References

1AuthorsMans B.J. Anantharaman V. Aravind L. Koonin E.V.
TitleComparative genomics, evolution and origins of the nuclear envelope and nuclear pore complex.
SourceCell Cycle 3:1612-1637(2004).
PubMed ID15611647

2AuthorsJaspersen S.L. Martin A.E. Glazko G. Giddings T.H. Jr. Morgan G. Mushegian A. Winey M.
TitleThe Sad1-UNC-84 homology domain in Mps3 interacts with Mps2 to connect the spindle pole body with the nuclear envelope.
SourceJ. Cell Biol. 174:665-675(2006).
PubMed ID16923827
DOI10.1083/jcb.200601062

3AuthorsGraumann K. Runions J. Evans D.E.
TitleCharacterization of SUN-domain proteins at the higher plant nuclear envelope.
SourcePlant J. 0:0-0(2009).
PubMed ID19807882
DOI10.1111/j.1365-313X.2009.04038.x



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