Authors

Discussion

The male germ cell-associated kinase (MAK) is known to play roles in meiosis, mitosis and ciliary length regulation in mammalian cells. However, very little is known about the MAK orthologues in kinetoplastids. Our study shows that TbMAK in bloodstream form Trypanosoma brucei is tightly regulated and essential in the cell cycle during late mitosis or early cytokinesis, as RNAi depletion or overexpression of TbMAK causes growth arrest together with an increase in cells with two nuclei (N) and two kinetoplasts (K), and later polyploid cells with abnormal NK complements, leading to eventual cell death. In contrast, in Leishmania mexicana promastigotes, LmxMAK appears to be non-essential or redundant since CRISPR ΔLmxMAK null mutants are viable in culture. TbMAK and LmxMAK show differential subcellular localisations, evidenced by CRISPR tagging of both proteins with mNeonGreen. While TbMAK:mNG mainly localises in between the nucleus and kinetoplast, possibly to the basal bodies and Golgi in bloodstream form T. brucei, LmxMAK:mNG is expressed in the flagellum and cytoplasm. To investigate whether LmxMAK plays any role in flagellum biogenesis or function, we have tagged the flagellar protein SMP1 in our null mutants and flagellum analysis is in progress. We are also setting up XL-BioID to investigate TbMAK and LmxMAK-interacting proteomes to understand the differences in MAK function in these related kinetoplastids.