Acts as guanine nucleotide exchange factor (GEF) for RAS proteins. Catalyzes the GDP-to-GTP exchange, resulting in an increase of the active GTP-bound form of HRAS (PubMed:20639119). Acts as a key modulator of PI3K-AKT signaling. . This is the function of Ensembl gene identifier ENSG00000100485 (SOS2, SOS Ras/Rho guanine nucleotide exchange factor 2).