{PDOC50181}
{PS50181; FBOX}
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* F-box domain profile *
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First identified in cyclin-F as a protein-protein interaction motif, the F-box
is a  conserved  domain  that  is present in numerous protein with a bipartite
structure [1].  Through  the  F-box,  these  proteins  are  linked to the Skp1
protein and  the  core  of  SCFs (Skp1-cullin-F-box protein ligase) complexes.
SCFs complexes  constitute  a  new  class  of E3 ligases [2]. They function in
combination with   the  E2  enzyme  Cdc34  to  ubiquitinate  G1  cyclins,  Cdk
inhibitors and  many other proteins, to mark them for degradation. The binding
of the specific substrates by SCFs complexes is mediated by divergent protein-
protein interaction  motifs  present in F-box proteins, like WD40 repeats (see
<PDOC00574>), leucine rich repeats [3,4] or ANK repeats (see <PDOC50088>).

Some proteins known to contain a F-box are listed below:

 - Mammalian G2/mitotic-specific cyclin-F.
 - Yeast CDC4. It contains WD repeats.
 - Yeast GRR1. It contains a leucine-rich segment.
 - Yeast MET30. It contains WD repeats.
 - Neurospora crassa Scon2. It contains WD repeats.
 - Emericella nidulans SconB. It contains WD repeats.
 - Caenorhabditis elegans sel-10. It contains WD repeats.
 - Xenopus laevis beta-TrCP. It contains WD repeats.
 - Poxviruses protein B18. They contain ANK repeats.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: 1.

-Expert(s) to contact by email:
           Hofmann K.; Kay.Hofmann@memorec.com

-Last update: December 2001 / First entry.

[ 1] Bai C., Sen P., Hofmann K., Ma L., Goebl M., Harper J.W.,
     Elledge S.J.
     "SKP1 connects cell cycle regulators to the ubiquitin proteolysis
     machinery through a novel motif, the F-box."
     Cell 86:263-274(1996).
     PubMed=8706131
[ 2] Skowyra D., Craig K.L., Tyers M., Elledge S.J., Harper J.W.
     "F-box proteins are receptors that recruit phosphorylated substrates
     to the SCF ubiquitin-ligase complex."
     Cell 91:209-219(1997).
     PubMed=9346238
[ 3] Krek W.
     "Proteolysis and the G1-S transition: the SCF connection."
     Curr. Opin. Genet. Dev. 8:36-42(1998).
     PubMed=9529603
[ 4] Craig K.L., Tyers M.
     "The F-box: a new motif for ubiquitin dependent proteolysis in cell
     cycle regulation and signal transduction."
     Prog. Biophys. Mol. Biol. 72:299-328(1999).
     PubMed=10581972

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