COS7 cells, transfected with GFP-PTP1B and APN-EphA3, when co-transfected with TM-BirA, yielded biotinylated EphA3 that can be stimulated with SA-Dynabeads. GFP-PTP1B and EphA3-transfected COS7 cells were stimulated with Alexa Fluor 594–ephrinA5–Fc–coated Protein A Dynabeads. Cell surface EphA3 was labelled on intact with anti-EphA3 mAb and detected with Alexa546-labelled secondary antibodies by confocal microscopy.