| 词条 | Btk-type zinc finger |
| 释义 |
| Symbol = BTK | Name = Btk motif | image = PDB 1bwn EBI.jpg | width = | caption = ph domain and btk motif from bruton's tyrosine kinase mutant e41k in complex with ins(1,3,4,5)p4 | Pfam = PF00779 | Pfam_clan = | InterPro = IPR001562 | SMART = BTK | PROSITE = | MEROPS = | SCOP = 1btk | TCDB = | OPM family = | OPM protein = | CAZy = | CDD = }} In molecular biology, the Btk-type zinc finger or Btk motif (BM) is a conserved zinc-binding motif containing conserved cysteines and a histidine that is present in certain eukaryotic signalling proteins. The motif is named after Bruton's tyrosine kinase (Btk), an enzyme which is essential for B cell maturation in humans and mice.[1][2] Btk is a member of the Tec family of protein tyrosine kinases (PTK). These kinases contain a conserved Tec homology (TH) domain between the N-terminal pleckstrin homology (PH) domain and the Src homology 3 (SH3) domain. The N-terminal of the TH domain is highly conserved and known as the Btf motif, while the C-terminal region of the TH domain contains a proline-rich region (PRR). The Btk motif contains a conserved His and three Cys residues that form a zinc finger (although these differ from known zinc finger topologies), while PRRs are commonly involved in protein-protein interactions, including interactions with G proteins.[3][4] The TH domain may be of functional importance in various signalling pathways in different species.[1] A complete TH domain, containing both the Btk and PRR regions, has not been found outside the Tec family; however, the Btk motif on its own does occur in other proteins, usually C-terminal to a PH domain (note that although a Btk motif always occurs C-terminal to a PH domain, not all PH domains are followed by a Btk motif). 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, and that the Btk motif is packed against the PH domain.[1] The zinc-binding residues are a histidine and three cysteines, which are fully conserved in the Btk motif.[5] Proteins known to contain a Btk-type zinc finger include:
References1. ^1 2 {{cite journal |vauthors=Vihinen M, Nilsson L, Smith CI | title = Tec homology (TH) adjacent to the PH domain | journal = FEBS Lett. | volume = 350 | issue = 2-3 | pages = 263–5 |date=August 1994 | pmid = 8070576 | doi = 10.1016/0014-5793(94)00783-7| url = }} {{InterPro content|IPR001562}}2. ^{{cite journal |vauthors=Lindvall JM, Blomberg KE, Valiaho J, Vargas L, Heinonen JE, Berglof A, Mohamed AJ, Nore BF, Vihinen M, Smith CI | title = Bruton's tyrosine kinase: cell biology, sequence conservation, mutation spectrum, siRNA modifications, and expression profiling | journal = Immunol. Rev. | volume = 203 | issue = | pages = 200–15 |date=February 2005 | pmid = 15661031 | doi = 10.1111/j.0105-2896.2005.00225.x | url = }} 3. ^{{cite journal |vauthors=Vihinen M, Nore BF, Mattsson PT, Backesjo CM, Nars M, Koutaniemi S, Watanabe C, Lester T, Jones A, Ochs HD, Smith CI | title = Missense mutations affecting a conserved cysteine pair in the TH domain of Btk | journal = FEBS Lett. | volume = 413 | issue = 2 | pages = 205–10 |date=August 1997 | pmid = 9280283 | doi = 10.1016/S0014-5793(97)00912-5| url = }} 4. ^{{cite journal |vauthors=Jiang Y, Ma W, Wan Y, Kozasa T, Hattori S, Huang XY | title = The G protein G alpha12 stimulates Bruton's tyrosine kinase and a rasGAP through a conserved PH/BM domain | journal = Nature | volume = 395 | issue = 6704 | pages = 808–13 |date=October 1998 | pmid = 9796816 | doi = 10.1038/27454 | url = }} 5. ^{{cite journal |vauthors=Hyvonen M, Saraste M | title = Structure of the PH domain and Btk motif from Bruton's tyrosine kinase: molecular explanations for X-linked agammaglobulinaemia | journal = EMBO J. | volume = 16 | issue = 12 | pages = 3396–404 |date=June 1997 | pmid = 9218782 | pmc = 1169965 | doi = 10.1093/emboj/16.12.3396 | url = }} 1 : Molecular biology |
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