Functions as a guanine exchange factor (GEF) for RAB26 and thus regulates autophagy of synaptic vesicles in axon terminal of motoneurons (By similarity). Involved in the control of neuronal cell differentiation (PubMed:11704860). Plays a role in angiogenesis through regulation of endothelial cells chemotaxis. Also affects the migration, adhesion, and matrix/bone degradation in macrophages and osteoclasts (PubMed:23777631). {ECO:0000250|UniProtKB:Q66T02, ECO:0000269|PubMed:11704860, ECO:0000269|PubMed:23777631}. This is the function of Ensembl gene identifier ENSG00000171680 (PLEKHG5, pleckstrin homology and RhoGEF domain containing G5).