... compilation ª 2011 FEBSMINIREVIEW TEC family kinases in health and disease – loss -of- function of BTK and ITK and the gain -of- function fusions ITK SYK and BTK SYKAlamdar Hussain1,2,*, Liang Yu1,3,*, ... phosphorylation levels of BTK SYK. ITK SYKwas highly phosphorylated in both COS7 and 293Tcells and did not vary like BTK SYK; therefore, the differences in the PH–TH domains remain the decisivefactor ... capacity, we constructed the corresponding fusion kinase BTK SYK, harboring the PH–TH domain doublet (amino acids 1–1 96) of BTK fused with the linker B kinase region of SYK(30 6–6 35 amino acids) (Fig....