Acts as an adapter protein that plays a role in intracellular signaling cascades triggered either by the cell surface activated epidermal growth factor receptor and/or cytoplasmic protein tyrosine kinases. Promotes activation of the MAPK/ERK signaling pathway. Plays a role in the regulation of cell proliferation (By similarity). Interacts with EGFR. Interacts (via proline-rich domain and phosphorylated at Tyr-105 and Tyr-453) with GRB2 (via SH3 domains); the interaction occurs upon EGF stimulation. Interacts (phosphorylated at Tyr-453) with PTPN11; the interaction increases MAPK/ERK activity and does not affect the GRB2/SOS complex formation (By similarity). On EGF stimulation, phosphorylated on Tyr-105 and Tyr-453. Belongs to the GAREM family. Truncated N-terminus.