Altered intracellular localization of the FU-Lck protein. Coimmunoprecipitation experiments were undertaken to determine the association of transgenic Lck proteins with CD4, CD8, and CD3ϵ. CD4 (A), CD8β (B), or CD3ϵ (C) were immunoprecipitated from thymocyte lysates using mAbs and protein-A Sepharose. Association of Lck^tg or FU-Lck^tg proteins was assessed by Western blot analysis using the V5 mAb. Data shown represent 1 of 3 repeated experiments.