EGFR complexes with and tyrosine phosphorylates GPRC5A. A, HEK293T cells were transfected with the plasmids encoding myc-tagged GPRC5A plus either EGFR or empty vector. Cells were treated with EGF (100 ng/ml) for different time periods as indicated. Cell lysates were harvest for Western blot using antibody PY99 (anti-pan-phospho-tyrosine), or anti-EGFR, or anti-myc-tag. B-C, Cells were co-transfected and treated as indicated. Treatment groups include: C- Control; E- EGF (100 ng/ml, 5 min); E + A- EGF + AG1478. Cell lysates were harvest for immuno- precipitation (IP)-Western blot analysis with antibodies as indicated.