title: BTK, the tyrosine kinase affected in X-linked agammaglobulinemia.
abstract: X-linked agammaglobulinemia (XLA) is a heritable immunodeficiency disorder that is caused by a differentiation block leading to almost complete absence of B lymphocytes and plasma cells. The affected protein is a cytoplasmic protein tyrosine kinase, Bruton's agammaglobulinemia tyrosine kinase (Btk). Btk along with Tec, Itk and Bmx belong to a distinct family of protein kinases. These proteins contain five regions; PH, TH, SH3, SH2 and kinase domains. Mutations causing XLA may affect any of these domains. About 200 unique mutations have been identified and are collected in a mutation database, BTKbase. Here, we describle, the structure, function, and interactions of the affected signaling molecules in atomic detail.
authors.affiliation: Department of Biosciences, Division of Biochemistry, P. O. Box 56, FIN-00014 University of Helsinki, Finland. mauno.vihinen@helsinki.fi
authors.forename: M
authors.initials: M
authors.lastname: Vihinen
authors.forename: P T
authors.initials: PT
authors.lastname: Mattsson
authors.forename: C I
authors.initials: CI
authors.lastname: Smith
mesh_terms: D000077329:Agammaglobulinaemia Tyrosine Kinase; D000361:Agammaglobulinemia; D000818:Animals; D008040:Genetic Linkage / Q000235:genetics*; D006801:Humans; D011505:Protein-Tyrosine Kinases / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D014960:X Chromosome / Q000235:genetics*
chemical_list: D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000625949:BTK protein, human