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UniProtKB/Swiss-Prot P08514: Variant p.Tyr174His

Integrin alpha-IIb
Gene: ITGA2B
Variant information

Variant position:  174
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Type of variant:  Disease [Disclaimer]
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 Histidine (H) at position 174 (Y174H, p.Tyr174His).
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 (H)
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 GT; abolishes the binding function of alpha-IIb/beta-3 for soluble ligands without disturbing alpha-IIb/beta-3 expression; functional defect is likely caused by its allosteric effect rather than by a defect in the ligand-binding site itself.
Any additional useful information about the variant.



Sequence information

Variant position:  174
The position of the amino-acid change on the UniProtKB canonical protein sequence.

Protein sequence length:  1039
The length of the canonical sequence.

Location on the sequence:   EKTPVGSCFLAQPESGRRAE  Y SPCRGNTLSRIYVENDFSWD
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                         EKTPVGSCFLAQPESGRRAEYSPCRGNTLSRIYVENDFSWD

Mouse                         EKTPVGGCFLAQLQSGGRAEYSPCRANTMSSVYAES-FRGD

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 32 – 1039 Integrin alpha-IIb
Chain 32 – 887 Integrin alpha-IIb heavy chain
Topological domain 32 – 993 Extracellular
Beta strand 171 – 174


Literature citations

A naturally occurring Tyr143His alpha IIb mutation abolishes alpha IIb beta 3 function for soluble ligands but retains its ability for mediating cell adhesion and clot retraction: comparison with other mutations causing ligand-binding defects.
Kiyoi T.; Tomiyama Y.; Honda S.; Tadokoro S.; Arai M.; Kashiwagi H.; Kosugi S.; Kato H.; Kurata Y.; Matsuzawa Y.;
Blood 101:3485-3491(2003)
Cited for: VARIANT GT HIS-174; CHARACTERIZATION OF VARIANT GT HIS-174;

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.