A cytoskeletal protein complex is essential for division of intracellular amastigotes of Leishmania mexicana

Felice D Kelly,Khoa D Tran,Jess Hatfield,Kat Schmidt,Marco A Sanchez,Scott M Landfear

doi:10.1074/jbc.ra120.014065

Felice D Kelly, Khoa D Tran + Show 4 more

Open Access

https://doi.org/10.1074/jbc.ra120.014065

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Abstract

Previous studies in Leishmania mexicana have identified the cytoskeletal protein KHARON as being important for both flagellar trafficking of the glucose transporter GT1 and for successful cytokinesis and survival of infectious amastigote forms inside mammalian macrophages. KHARON is located in three distinct regions of the cytoskeleton: the base of the flagellum, the subpellicular microtubules, and the mitotic spindle. To deconvolve the different functions for KHARON, we have identified two partner proteins, KHAP1 and KHAP2, which associate with KHARON. KHAP1 is located only in the subpellicular microtubules, whereas KHAP2 is located at the subpellicular microtubules and the base of the flagellum. Both KHAP1 and KHAP2 null mutants are unable to execute cytokinesis but are able to traffic GT1 to the flagellum. These results confirm that KHARON assembles into distinct functional complexes and that the subpellicular complex is essential for cytokinesis and viability of disease-causing amastigotes but not for flagellar membrane trafficking.

Highlights

Leishmania are parasitic protists responsible for an estimated 12 million infections worldwide with pathologies ranging from self-healing cutaneous disease to fatal visceral leishmaniasis [1]
KH could be responsible for trafficking of other unknown proteins into the amastigote flagellum, a distinct possibility is that the failure of Dkh amastigotes to undergo cytokinesis may reflect a function of KH located at other sites within the parasite, either on the subpellicular cytoskeleton or in the mitotic spindle
We suggest that there may be three such complexes, KH Complex 1 located at the base of the flagellum, KH Complex 2 located on the subpellicular microtubules, and KH Complex 3 associated with the mitotic spindle

Summary

Introduction

Leishmania are parasitic protists responsible for an estimated 12 million infections worldwide with pathologies ranging from self-healing cutaneous disease to fatal visceral leishmaniasis [1]. Fluorescence microscopy and quantitative analysis of such images (Fig. 7, C–F) establish that each of these proteins traffics well to the flagellar membrane in WT and Dkh null mutant promastigotes and that KH is not required for efficient flagellar trafficking of several integral membrane proteins with diverse localization patterns in this organellar membrane.

Results

Conclusion