|PROSITE documentation PDOC51113|
The Btk-type zinc finger or Btk motif (BM) is a domain of ~37 amino acids present in eukaryotic signalling proteins. The domain is named after Bruton's tyrosine kinase (Btk), an enzyme which is essential for B cell maturation in humans and mice [1,2]. Btk and other protein tyrosine kinases (PTK) of the Tec family contain a conserved Tec homology (TH) region between the N-terminal pleckstrin homology (PH) domain (see <PDOC50003>) and the Src homology 3 (SH3) domain (see <PDOC50002>). The Btk domain forms the N-terminal part of the Tec homology region while the C-terminal portion of TH contains a proline-rich region. The Btk domain occurs in some proteins outside the Tec family of PTKs, where it is also C-terminal to a PH domain. The Btk-type zinc finger seems to be involved in protein-protein interactions, and it can interact with G proteins [3,4].
The crystal structures of Btk show that the Btk-type zinc finger has a globular core, formed by a long loop which is held together by a zinc ion (see <PDB:1BTK>). The zinc-binding residues are a histidine and three cysteines, which are fully conserved in the Btk motif [1,2,3,4,5].
Some proteins known to contain a Btk-type zinc finger:
The profile we developed covers the entire Btk-type zinc finger.Last update:
April 2005 / First entry.
PROSITE method (with tools and information) covered by this documentation:
|1||Authors||Vihinen M. Nilsson L. Smith C.I.E.|
|Title||Tec homology (TH) adjacent to the PH domain.|
|Source||FEBS Lett. 350:263-265(1994).|
|2||Authors||Lindvall J.M. Blomberg K.E.M. Valiaho J. Vargas L. Heinonen J.E. Berglof A. Mohamed A.J. Nore B.F. Vihinen M. Smith C.I.E.|
|Title||Bruton's tyrosine kinase: cell biology, sequence conservation, mutation spectrum, siRNA modifications, and expression profiling.|
|Source||Immunol. Rev. 203:200-215(2005).|
|3||Authors||Vihinen M. Nore B.F. Mattsson P.T. Backesjo C.M. Nars M. Koutaniemi S. Watanabe C. Lester T. Jones A. Ochs H.D. Smith C.I.E.|
|Title||Missense mutations affecting a conserved cysteine pair in the TH domain of Btk.|
|Source||FEBS Lett. 413:205-210(1997).|
|4||Authors||Jiang Y. Ma W. Wan Y. Kozasa T. Hattori S. Huang X.Y.|
|Title||The G protein G alpha12 stimulates Bruton's tyrosine kinase and a rasGAP through a conserved PH/BM domain.|
|5||Authors||Hyvonen M. Saraste M.|
|Title||Structure of the PH domain and Btk motif from Bruton's tyrosine kinase: molecular explanations for X-linked agammaglobulinaemia.|
|Source||EMBO J. 16:3396-3404(1997).|