Detection Of The Homo- Or Hetero-interaction Of Doks With Fluorescence Resonance Energy Transfer In Living Cells

Protein-protein interactions are fundamental to living systems. Dynamic association and dissociation of protein complexes control most cellular functions, including cell cycle progression, signal transduction, and metabolic pathways. The adaptor protein has reported to function by homo- or hetero-interaction. Adaptor protein Doks can be phosphorylated as a common substrate for activated protein tyrosine kinases (PTK) and receptor protein tyrosine kinases (RTK). It is reported that there is homo-or hetero-interaction between Dokl and Dok2. It is not clear whether there is homo- or hetero-interaction within other members of Doks family. Here, we have successfully set up a FRET imaging system, which can be used to detect protein interactions effectively in living cells. Based on this system, the homo- and hetero-interaction of Dok5 and Dokl were demonstrated for the first time. Furthermore, PH domain and PTB domain in Dokl were found to be critical for both homo-interaction of Dokl and hetero-interaction between Dokl and Dok5. In addition, PTB domain in Dok5 was essential for oligomerization of Dok5, although the PTB domain and the COOH domain were also important for homo-interaction of Dok5.