Plasma membrane-associated small GTPase which cycles between an active GTP-bound and an inactive GDP-bound state. Causes the formation of thin, actin-rich surface projections called filopodia. Functions cooperatively with CDC42 and Rac to generate additional structures, increasing the diversity of actin-based morphology. This is the function of Ensembl gene identifier ENSG00000139725 (RHOF, ras homolog family member F, filopodia associated).