| Type: | Domain | Name: | SUN domain |
| Description: | Sad1/UNC-84 (SUN)-domain proteins are inner nuclear membrane (INM) proteins that are part of bridging complexes linking cytoskeletal elements with thenucleoskeleton. Originaly identified based on an ~150-amino acid region of homology between the C terminus of the Schizosaccharomyces pombe Sad1 proteinand the Caenorhabditis elegans UNC-84 protein, SUN proteins are present in the proteomes of most eucaryotes. In addition to the SUN domain, these proteinscontain a transmembrane sequence and at least one coiled-coil domain and localise to the inner nuclear envelope. SUN proteins are anchored in the innernuclear envelope by their transmembrane segment and oriented in the membrane such that the C-terminal SUN domain is located in the space between the innerand outer nuclear membrane. Here, the SUN domain can interact with the C- terminal tail of an outer nuclear envelope protein that binds to thecytoskeleton, including the centrosome [, , ].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 uncharacterised 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 organisation and assembly of outer dense fibres (ODFs), a specific structure of the sperm tail.Mammalian sperm-associated antigen 4-like protein (SPAG4L).Mammalian SUN1.Mammalian SUN2.Mammalian SUN3. | Short Name: | SUN_dom |
