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UniProtKB/Swiss-Prot O43683: Variant p.Tyr259Cys

Mitotic checkpoint serine/threonine-protein kinase BUB1
Gene: BUB1
Chromosomal location: 2q12-q13
Variant information

Variant position:  259
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 Tyrosine (Y) to Cysteine (C) at position 259 (Y259C, p.Tyr259Cys).
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 large size and aromatic (Y) to medium size and polar (C)
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 pancreatic cancer; associated with N-265; failure to rescue the spindle-assembly checkpoint activity as a result of a deficient recruitment of MAD2L1 and BUBR1 to kinetochores; efficient restoration of chromosome congression; reduced binding to BUB3; rescue of the ability of kinetochores to bind SGO1 and CENPF but not MCAK.
Any additional useful information about the variant.

Sequence information

Variant position:  259
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  1085
The length of the canonical sequence.

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.


Mouse                         KEK------LIRGDSEFSFEELRAQK-----YNQRKKHEQW

Caenorhabditis elegans        EEF------RFAKWKDTFGEDVDDDY-----RKRKDSGVVF


Baker's yeast                 NQR------LKNGNKKTS------IY-----ADQKQSNNPV

Fission yeast                 ------------------------LE-----SEANTPNLPL

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.

Chain 1 – 1085 Mitotic checkpoint serine/threonine-protein kinase BUB1

Literature citations

Bub1 regulates chromosome segregation in a kinetochore-independent manner.
Klebig C.; Korinth D.; Meraldi P.;
J. Cell Biol. 185:841-858(2009)

A double missense variation of the BUB1 gene and a defective mitotic spindle checkpoint in the pancreatic cancer cell line Hs766T.
Hempen P.M.; Kurpad H.; Calhoun E.S.; Abraham S.; Kern S.E.;
Hum. Mutat. 21:445-445(2003)

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.