Systematic analysis of Plasmodium myosins reveals differential expression, localisation, and function in invasive and proliferative parasite stages

Abstract

The myosin superfamily comprises of actin‐dependent eukaryotic molecular motors important in a variety of cellular functions. Although well studied in many systems, knowledge of their functions in Plasmodium, the causative agent of malaria, is restricted. Previously, six myosins were identified in this genus, including three Class XIV myosins found only in Apicomplexa and some Ciliates. The well characterized MyoA is a Class XIV myosin essential for gliding motility and invasion. Here, we characterize all other Plasmodium myosins throughout the parasite life cycle and show that they have very diverse patterns of expression and cellular location. MyoB and MyoE, the other two Class XIV myosins, are expressed in all invasive stages, with apical and basal locations, respectively. Gene deletion revealed that MyoE is involved in sporozoite traversal, MyoF and MyoK are likely essential in the asexual blood stages, and MyoJ and MyoB are not essential. Both MyoB and its essential light chain (MCL‐B) are localised at the apical end of ookinetes but expressed at completely different time points. This work provides a better understanding of the role of actomyosin motors in Apicomplexan parasites, particularly in the motile and invasive stages of Plasmodium during sexual and asexual development within the mosquito.

Plasmodium bergheikinesin-5 associates with the spindle apparatus during cell division and is important for efficient production of infectious sporozoites

“…The location of kinesin-5 in the residual body of mature oocysts following release of sporozoites, suggests that kinesin-5 is actively involved during mitosis in oocysts and then it is discarded at the end of endomitotic cell division. A similar fate was also observed for another molecular motor, myosin J (MyoJ) that also accumulates in the residual body during sporogony [42].…”

“…Sporozoites were isolated from salivary glands of mosquitoes infected with WT-GFP and Δ kinesin-5 parasites on day 21 post infection. Isolated sporozoites in RPMI 1640 containing 3% bovine serum albumin (Fisher Scientific) were pelleted (5 min, 5,000 rpm, 4°C) and used for motility assays as described previously [42]. Briefly, a drop (6 arginyl-t RNA synthetase (PBANKA_143420) genes were used as endogenous control reference genes.…”

Plasmodium berghei Kinesin-5 Associates With the Spindle Apparatus During Cell Division and Is Important for Efficient Production of Infectious Sporozoites

“…The location of kinesin-5 in the residual body of mature oocysts following release of sporozoites, suggests that kinesin-5 is actively involved during mitosis in oocysts and then it is discarded at the end of endomitotic cell division. A similar fate was also observed for another molecular motor, myosin J (MyoJ) that also accumulates in the residual body during sporogony ( Wall et al., 2019 ).…”

“…Sporozoites were isolated from salivary glands of mosquitoes infected with WT‐GFP and Δkinesin-5 parasites on day 21 post-infection. Isolated sporozoites in RPMI 1640 containing 3% bovine serum albumin (Fisher Scientific) were pelleted (5 min, 5,000 rpm, 4°C) and used for motility assays as described previously ( Wall et al., 2019 ). Briefly, a drop (6 μl) of sporozoites was transferred onto a microscope glass slide with a cover slip.…”

High-resolution structures of malaria parasite actomyosin and actin filaments

“…Plasmodium spp. have six myosin genes; three parasite-specific class XIV myosins, two reverse-directed class VI myosins, and one class XXII myosin (8). One of the class XIV myosins, PfMyoA, is essential for gliding motility and is the bestcharacterized of the parasite myosins.…”