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UniProtKB/Swiss-Prot Q9UKT5: Variant p.Leu23Gln

F-box only protein 4
Gene: FBXO4
Variant information

Variant position:  23
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Unclassified
The variants are classified into three categories: Disease, Polymorphism and Unclassified.
  • Disease: Variants implicated in disease according to literature reports.
  • Polymorphism: Variants not reported to be implicated in disease.
  • Unclassified: Variants with uncertain implication in disease according to literature reports. Evidence against or in favor of a pathogenic role is limited and/or conflicting.

Residue change:  From Leucine (L) to Glutamine (Q) at position 23 (L23Q, p.Leu23Gln).
Indicates the amino acid change of the variant. The one-letter and three-letter codes for amino acids used in UniProtKB/Swiss-Prot are those adopted by the commission on Biochemical Nomenclature of the IUPAC-IUB.

Physico-chemical properties:  Change from medium size and hydrophobic (L) to medium size and polar (Q)
The physico-chemical property of the reference and variant residues and the change implicated.

BLOSUM score:  -2
The score within a Blosum matrix for the corresponding wild-type to variant amino acid change. The log-odds score measures the logarithm for the ratio of the likelihood of two amino acids appearing by chance. The Blosum62 substitution matrix is used. This substitution matrix contains scores for all possible exchanges of one amino acid with another:
  • Lowest score: -4 (low probability of substitution).
  • Highest score: 11 (high probability of substitution).
More information can be found on the following page

Variant description:  In esophagus cancer samples.
Any additional useful information about the variant.



Sequence information

Variant position:  23
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  387
The length of the canonical sequence.

Location on the sequence:   GSEPRSGTNSPPPPFSDWGR  L EAAILSGWKTFWQSVSKERV
The residue change on the sequence. Unless the variant is located at the beginning or at the end of the protein sequence, both residues upstream (20) and downstream (20) of the variant will be shown.

Residue conservation: 
The multiple alignment of the region surrounding the variant against various orthologous sequences.

Human                         GSEPRSGTNSPPPPFSDWGRLEAAILSGWKTFWQSVSKERV

Mouse                         GSEPRGAGS--PPPASDWGRLEAAILSGWRTFWYSVAKERA

Bovine                        GSDPGSRGSSPQPPHSDWGRLEAAFLSGWRNFWQSVGKERA

Sequence annotation in neighborhood:  
The regions or sites of interest surrounding the variant. In general the features listed are posttranslational modifications, binding sites, enzyme active sites, local secondary structure or other characteristics reported in the cited references. The "Sequence annotation in neighborhood" lines have a fixed format:
  • Type: the type of sequence feature.
  • Positions: endpoints of the sequence feature.
  • Description: contains additional information about the feature.

TypePositionsDescription
Chain 1 – 387 F-box only protein 4
Modified residue 12 – 12 Phosphoserine
Mutagenesis 12 – 12 S -> A. Reduces homodimerization. Reduces ubiquitination of CCND1.
Mutagenesis 12 – 12 S -> E. No effect on homodimerization.
Mutagenesis 13 – 13 P -> A. Reduces homodimerization.
Mutagenesis 23 – 23 L -> A. Abolishes homodimerization.


Literature citations

Mutations in Fbx4 inhibit dimerization of the SCF(Fbx4) ligase and contribute to cyclin D1 overexpression in human cancer.
Barbash O.; Zamfirova P.; Lin D.I.; Chen X.; Yang K.; Nakagawa H.; Lu F.; Rustgi A.K.; Diehl J.A.;
Cancer Cell 14:68-78(2008)
Cited for: FUNCTION; SUBUNIT; INTERACTION WITH SKP1; PHOSPHORYLATION AT SER-12; VARIANTS ARG-8; LEU-12; SER-13; GLN-23 AND THR-76; CHARACTERIZATION OF VARIANTS LEU-12; SER-13 AND GLN-23;

Disclaimer: Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. They are not in any way intended to be used as a substitute for professional medical advice, diagnostic, treatment or care.