Toxoplasma gondii, the causative agent of toxoplasmosis, is a highly ubiqitous pathogen infecting 30-80% of human populations and is the cause of congenital birth defects, blindness and disease of immunocompromised individuals. Like all apicomplexan species, including the malaria parasite Plasmodium spp., Toxoplasma undergoes a unique form of motility - termed gliding motility to move through tissue and invade host cells. At its heart, apicomplexan gliding motility is driven by a conserved actinomyosin-based motor termed- the 'glideosome'- which lies just beneath the plasma membrane and comprises an unusual myosin - MyoA- anchored to the periphery by its light chain MLC1. We have recently identified that Toxoplasma MyoA also has two other light chains, defining the 'lever arm' and providing evidence of how this molecular motor is regulated and pivots to undertake its powerstroke to drive gliding motility. Using conditional knockouts we demonstrate that the ELC1 and 2 are in fact redundant and are required for Toxoplasma to undergo host cell egress, tissue dissemination and host cell invasion. Furthermore, we show using molecular modelling and mutational analysis that Ca2+ binding to the ELC1/2 is likely required for the MyoA lever arm rigidity by providing an interaction face between ELC1/2 and MLC1. We have now isolated native glideosome and have demonstrated the role ELC1/2 - lever arm interaction in binding to actin filaments, undergoing ATP turnover and providing a rigid structure for the MyoA head to pivot against. Furthermore, we have begun to the reveal the structure of the 650kD glideosome using single particle imaging under cryogenic temperatures to gain mechanistic insight into how this molecular motor drives motility in apicomplexan parasites.