Bruton's tyrosine kinase (Btk) of the Tec family possesses a Pleckstrin homology (PH) domain, which is responsible for plasma membrane targeting. In this study, the crystal structure of the Btk PH domain in complex with dibutylyl-phosphatidylinositol-3,4,5-triphosphate was determined ...
Bruton's tyrosine kinase (Btk) of the Tec family possesses a Pleckstrin homology (PH) domain, which is responsible for plasma membrane targeting. In this study, the crystal structure of the Btk PH domain in complex with dibutylyl-phosphatidylinositol-3,4,5-triphosphate was determined. The structure revealed that the Btk PH domain forms a homodimer and that each molecule binds phosphatidylinositol in the binding pocket. The side chain of Lys18 within a Btk-specific insertion in the beta1-beta2 loop is able to form a hydrogen bond with the diacylglycerol moiety of phosphatidylinositol. The other Btk-specific insertion in the beta5-beta6 loop constitutes the dimerization interface. Thus, the modes of phosphatidylinositol recognition and Btk PH domain dimerization are distinct from those of other PH domains.
Organizational Affiliation:
Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan.
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