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  Domain Name: PH_Btk
Bruton's tyrosine kinase pleckstrin homology (PH) domain. Btk is a member of the Tec family of cytoplasmic protein tyrosine kinases that includes BMX, IL2-inducible T-cell kinase (Itk) and Tec. Btk plays a role in the maturation of B cells. Tec proteins general have an N-terminal PH domain, followed by a Tek homology (TH) domain, a SH3 domain, a SH2 domain and a kinase domain. The Btk PH domain binds phosphatidylinositol 3,4,5-trisphosphate and responds to signalling via phosphatidylinositol 3-kinase. The PH domain is also involved in membrane anchoring which is confirmed by the discovery of a mutation of a critical arginine residue in the BTK PH domain. This results in severe human immunodeficiency known as X-linked agammaglobulinemia (XLA) in humans and a related disorder is mice.PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.
No pairwise interactions are available for this conserved domain.

Total Mutations Found: 6
Total Disease Mutations Found: 3
This domain occurred 22 times on human genes (39 proteins).


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 The histograms below the weblogo indicate mutations found on the domain. Red is for disease (OMIM) and blue is for SNPs.

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Range on the Protein:  

   Protein ID            Protein Position

Domain Position:  

Feature Name:Total Found:
phosphoinositide binding
Zn binding site
homodimer interface

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Please Cite: Peterson, T.A., Adadey, A., Santana-Cruz ,I., Sun, Y., Winder A, Kann, M.G., (2010) DMDM: Domain Mapping of Disease Mutations. Bioinformatics 26 (19), 2458-2459.

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