Enables semaphorin receptor activity. Involved in epidermis development; nematode male tail mating organ morphogenesis; and nematode male tail tip morphogenesis. Located in ruffle membrane. Expressed in several structures, including DA9; epithelial cell; non-striated muscle; somatic nervous system; and tail. Is an ortholog of several human genes including PLXNA1 (plexin A1); PLXNA2 (plexin A2); and PLXNA3 (plexin A3).