{PDOC51469}
{PS51469; SUN}
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* SUN domain profile *
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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.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: November 2009 / First entry.

[ 1] Mans B.J., Anantharaman V., Aravind L., Koonin E.V.
     "Comparative genomics, evolution and origins of the nuclear envelope
     and nuclear pore complex."
     Cell Cycle 3:1612-1637(2004).
     PubMed=15611647
[ 2] Jaspersen S.L., Martin A.E., Glazko G., Giddings T.H. Jr., Morgan G.,
     Mushegian A., Winey M.
     "The Sad1-UNC-84 homology domain in Mps3 interacts with Mps2 to
     connect the spindle pole body with the nuclear envelope."
     J. Cell Biol. 174:665-675(2006).
     PubMed=16923827; DOI=10.1083/jcb.200601062
[ 3] Graumann K., Runions J., Evans D.E.
     "Characterization of SUN-domain proteins at the higher plant nuclear
     envelope."
     Plant J. 0:0-0(2009).
     PubMed=19807882; DOI=10.1111/j.1365-313X.2009.04038.x

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