PURPOSE: The Dok proteins represent a family of adaptor proteins serving as common substrates for protein tyrosine kinases and play an important role in regulating signal transduction in multiple cell functions. Dimerization of Dok proteins may represent a powerful and flexible regulatory mechanism that can achieve a variety of consequences. This study aims to detect the homo- or hetero-association of Doks in living cells. PROCEDURE: The transfection of CFP or YFP fusion protein constructs was carried out using lipofectamine 2000. FRET Measurements were performed using three-channel microscopy and Spectroscopy. RESULTS: By using fluorescence resonance energy transfer technology, we demonstrated, for the first time to our knowledge, that Dok5 and Dok1 could form homomeric and heteromeric associations in living cells. Moreover, pleckstrin homology (PH) domain was found to be essential for homomeric associations of Dok5, while PH domain and phosphotyrosine binding domain were found to be crucial for homomeric associations of Dok1 or heteromeric associations between Dok1 and Dok5. CONCLUSION: The mechanisms underlying Doks' association may benefit the further understanding of the important role of Dok proteins in regulating signal transduction activated by tyrosine kinases.
PURPOSE: The Dok proteins represent a family of adaptor proteins serving as common substrates for protein tyrosine kinases and play an important role in regulating signal transduction in multiple cell functions. Dimerization of Dok proteins may represent a powerful and flexible regulatory mechanism that can achieve a variety of consequences. This study aims to detect the homo- or hetero-association of Doks in living cells. PROCEDURE: The transfection of CFP or YFP fusion protein constructs was carried out using lipofectamine 2000. FRET Measurements were performed using three-channel microscopy and Spectroscopy. RESULTS: By using fluorescence resonance energy transfer technology, we demonstrated, for the first time to our knowledge, that Dok5 and Dok1 could form homomeric and heteromeric associations in living cells. Moreover, pleckstrin homology (PH) domain was found to be essential for homomeric associations of Dok5, while PH domain and phosphotyrosine binding domain were found to be crucial for homomeric associations of Dok1 or heteromeric associations between Dok1 and Dok5. CONCLUSION: The mechanisms underlying Doks' association may benefit the further understanding of the important role of Dok proteins in regulating signal transduction activated by tyrosine kinases.