Guanyl-nucleotide exchange factor of the RHOG GTPase stimulating the exchange of RHOG-associated GDP for GTP. May play a role in chemotactic cell migration by mediating the activation of RAC1 by EPHA2. May also activate CDC42 and mediate activation of CDC42 by the viral protein HPV16 E6. . This is the function of ARHGEF16 (Rho guanine nucleotide exchange factor 16, Ensembl gene identifier ENSG00000130762).