Regulates the activity of DOCK guanine nucleotide exchange factors (GEFs) (PubMed:11595183, PubMed:12134158, PubMed:32651375, PubMed:38857861). Acts in association with DOCK1, DOCK2, DOCK5 and CRK (PubMed:11595183, PubMed:12134158, PubMed:32651375, PubMed:38857861). Promotes RAC1 activation by DOCK5; the activity is stimulated by RHOG (PubMed:38857861). Involved in cytoskeletal rearrangements required for phagocytosis of apoptotic cells and cell motility (PubMed:11595183). {ECO:0000269|PubMed:11595183, ECO:0000269|PubMed:12134158, ECO:0000269|PubMed:32651375, ECO:0000269|PubMed:38857861}. This is the function of ELMO1 (engulfment and cell motility 1, Ensembl gene identifier ENSG00000155849).