Accession: | |
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Functional site class: | Cyclin docking motif |
Functional site description: | Substrate recognition site that interacts with cyclin and thereby increases phosphorylation by cyclin/Cdk complexes. Predicted proteins should have a Cdk phosphorylation site. Also used by cyclin/Cdk inhibitors. |
ELM Description: | The classical cyclin docking motif pattern is mainly derived from peptides bound to Cyclin A, for which there are several structures in complex with the peptide. Although the motif is often called RxL, there are actually four core binding residues, with only the Leucine being fully conserved. The motif binds in a hydrophobic groove with charged residues lining the edge. Peptide backbone hydrogen bonds guide the four core binding residues into the groove. Preceding the core motif, there is a clear but non-essential preference for basic residues. After the core, there is a clear but flexible preference for acidic residues. The first core binding position is quite shallow, accepting either hydrophobic or basic residues. It is followed by a residue facing outwards which cannot accept the short acidic residue Asp. The next residue lies in a pocket and must be either Arg or Lys. It is followed by a residue facing outwards which cannot accept the short acidic residue Asp. Then comes the Leu residue fitting into the hydrophobic groove. Flexible spacing then allows one optional externally facing residue. The final core hydrophobic residue is one of Phe, Pro, Leu or Met. The derived regular expression pattern captures the core motif and approximates the weaker charge preference to either side. |
Pattern: | (.|([KRH].{0,3}))[^EDWNSG][^D][RK][^D]L.{0,1}[FLMP].{0,3}[EDST] |
Pattern Probability: | 0.0042105 |
Present in taxon: | Eukaryota |
Interaction Domain: |
Cyclin_N (PF00134)
Cyclin, N-terminal domain
(Stochiometry: 1 : 1)
|
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The cyclin recognition site (alias Cy or RxL motif) is found in a wide range of cyclin/CDK interacting proteins (Wohlschlegel,2001). The presence of this docking motif in Cdk substrates substantially increases the level of phosphorylation at ([ST])Px(0,2)[KR] motifs (MOD_CDK_SPxK_1). Example proteins are the retinoblastoma protein, E2F1-3, and p53. Much of Cdk phosphorylation activity occurs during the cell cycle (Loog,2005). Much Cdk phosphorylation occurs in the nucleus but some Cdks are also active in the cytoplasm: For example, the cytoplasmic SRC and TAU proteins are known CDK targets. The motif is recognised by a conserved region in the cyclin protein and binds in a similar manner as the p21Kip cyclin inhibitor (1JSU) which hides the site from substrates. In mammals, the cyclin-binding RxL motif is best described for Cyclin A (Schulman,1998). It is likely that some of the other cyclins may have different specificities that are not yet described. In yeast, for example, cyclin Cln2 binds a hydrophobic LLPP motif (Ear,2013; Bhaduri,2011). |



(click table headers for sorting; Notes column: =Number of Switches, =Number of Interactions)
Please cite:
The eukaryotic linear motif resource - 2018 update.
(PMID:29136216)
ELM data can be downloaded & distributed for non-commercial use according to the ELM Software License Agreement
ELM data can be downloaded & distributed for non-commercial use according to the ELM Software License Agreement