Flagellin is the subunit protein which polymerizes to form the filaments of bacterial flagella. Heteromer of multiple flagellin subunits including FlaA, FlaB/D, FlaC, FlaE and FlaF. V.parahaemolyticus possesses two flagellar systems: a single polar flagellum propels the bacterium in liquid (swimming), while multiple lateral (peritrichous) flagella move the bacterium over surfaces (swarming). The polar flagellum is synthesized constitutively but lateral flagella are produced only under conditions in which the polar flagellum is not functional. Belongs to the bacterial flagellin family.