| Phosphorylation at Tyr 838 in the kinase domain of EphA 8 modulates Fyn binding to the Tyr 615 site by enhancing tyrosine kinase activity . ^^^ In vitro binding experiments revealed that phosphorylation at Tyr 615 in EphA 8 mediates the preferential binding to Fyn SH 2 domain rather than Src and Ras GTPase activating protein ( Ras GAP ) SH 2 domains . ^^^ Additionally , a high level of EphA 8 was detected in Fyn immunoprecipitates in intact cells , indicating that EphA 8 and Fyn can physically associate in vivo . ^^^ In contrast , the association of full length Fyn to EphA 8 containing mutation at either Tyr 615 or Tyr 838 was greatly reduced . ^^^ Furthermore , transient expression of kinase inactive Fyn in EphA 8 overexpressing cells blocked cell attachment responses attenuated by the EphA 8 signaling . ^^^ |