Two Essential Light Chains Regulate the MyoA Lever Arm To Promote <italic toggle="yes">Toxoplasma</italic> Gliding Motility

ABSTRACT Key to the virulence of apicomplexan parasites is their ability to move through tissue and to invade and egress from host cells. Apicomplexan motility requires the activity of the glideosome, a multicomponent molecular motor composed of a type XIV myosin, MyoA. Here we identify a novel glid...

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Autores principales:	Melanie J. Williams, Hernan Alonso, Marta Enciso, Saskia Egarter, Lilach Sheiner, Markus Meissner, Boris Striepen, Brian J. Smith, Christopher J. Tonkin
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2015
Materias:	Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/d0c460df28c34814998e886ac78c3a7f
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spelling	oai:doaj.org-article:d0c460df28c34814998e886ac78c3a7f2021-11-15T15:41:31ZTwo Essential Light Chains Regulate the MyoA Lever Arm To Promote <italic toggle="yes">Toxoplasma</italic> Gliding Motility10.1128/mBio.00845-152150-7511https://doaj.org/article/d0c460df28c34814998e886ac78c3a7f2015-10-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mBio.00845-15https://doaj.org/toc/2150-7511ABSTRACT Key to the virulence of apicomplexan parasites is their ability to move through tissue and to invade and egress from host cells. Apicomplexan motility requires the activity of the glideosome, a multicomponent molecular motor composed of a type XIV myosin, MyoA. Here we identify a novel glideosome component, essential light chain 2 (ELC2), and functionally characterize the two essential light chains (ELC1 and ELC2) of MyoA in Toxoplasma. We show that these proteins are functionally redundant but are important for invasion, egress, and motility. Molecular simulations of the MyoA lever arm identify a role for Ca2+ in promoting intermolecular contacts between the ELCs and the adjacent MLC1 light chain to stabilize this domain. Using point mutations predicted to ablate either the interaction with Ca2+ or the interface between the two light chains, we demonstrate their contribution to the quality, displacement, and speed of gliding Toxoplasma parasites. Our work therefore delineates the importance of the MyoA lever arm and highlights a mechanism by which this domain could be stabilized in order to promote invasion, egress, and gliding motility in apicomplexan parasites. IMPORTANCE Tissue dissemination and host cell invasion by apicomplexan parasites such as Toxoplasma are pivotal to their pathogenesis. Central to these processes is gliding motility, which is driven by an actomyosin motor, the MyoA glideosome. Others have demonstrated the importance of the MyoA glideosome for parasite motility and virulence in mice. Disruption of its function may therefore have therapeutic potential, and yet a deeper mechanistic understanding of how it works is required. Ca2+-dependent and -independent phosphorylation and the direct binding of Ca2+ to the essential light chain have been implicated in the regulation of MyoA activity. Here we identify a second essential light chain of MyoA and demonstrate the importance of both to Toxoplasma motility. We also investigate the role of Ca2+ and the MyoA regulatory site in parasite motility and identify a potential mechanism whereby binding of a divalent cation to the essential light chains could stabilize the myosin to allow productive movement.Melanie J. WilliamsHernan AlonsoMarta EncisoSaskia EgarterLilach SheinerMarkus MeissnerBoris StriepenBrian J. SmithChristopher J. TonkinAmerican Society for MicrobiologyarticleMicrobiologyQR1-502ENmBio, Vol 6, Iss 5 (2015)
institution	DOAJ
collection	DOAJ
language	EN
topic	Microbiology QR1-502
spellingShingle	Microbiology QR1-502 Melanie J. Williams Hernan Alonso Marta Enciso Saskia Egarter Lilach Sheiner Markus Meissner Boris Striepen Brian J. Smith Christopher J. Tonkin Two Essential Light Chains Regulate the MyoA Lever Arm To Promote <italic toggle="yes">Toxoplasma</italic> Gliding Motility
description	ABSTRACT Key to the virulence of apicomplexan parasites is their ability to move through tissue and to invade and egress from host cells. Apicomplexan motility requires the activity of the glideosome, a multicomponent molecular motor composed of a type XIV myosin, MyoA. Here we identify a novel glideosome component, essential light chain 2 (ELC2), and functionally characterize the two essential light chains (ELC1 and ELC2) of MyoA in Toxoplasma. We show that these proteins are functionally redundant but are important for invasion, egress, and motility. Molecular simulations of the MyoA lever arm identify a role for Ca2+ in promoting intermolecular contacts between the ELCs and the adjacent MLC1 light chain to stabilize this domain. Using point mutations predicted to ablate either the interaction with Ca2+ or the interface between the two light chains, we demonstrate their contribution to the quality, displacement, and speed of gliding Toxoplasma parasites. Our work therefore delineates the importance of the MyoA lever arm and highlights a mechanism by which this domain could be stabilized in order to promote invasion, egress, and gliding motility in apicomplexan parasites. IMPORTANCE Tissue dissemination and host cell invasion by apicomplexan parasites such as Toxoplasma are pivotal to their pathogenesis. Central to these processes is gliding motility, which is driven by an actomyosin motor, the MyoA glideosome. Others have demonstrated the importance of the MyoA glideosome for parasite motility and virulence in mice. Disruption of its function may therefore have therapeutic potential, and yet a deeper mechanistic understanding of how it works is required. Ca2+-dependent and -independent phosphorylation and the direct binding of Ca2+ to the essential light chain have been implicated in the regulation of MyoA activity. Here we identify a second essential light chain of MyoA and demonstrate the importance of both to Toxoplasma motility. We also investigate the role of Ca2+ and the MyoA regulatory site in parasite motility and identify a potential mechanism whereby binding of a divalent cation to the essential light chains could stabilize the myosin to allow productive movement.
format	article
author	Melanie J. Williams Hernan Alonso Marta Enciso Saskia Egarter Lilach Sheiner Markus Meissner Boris Striepen Brian J. Smith Christopher J. Tonkin
author_facet	Melanie J. Williams Hernan Alonso Marta Enciso Saskia Egarter Lilach Sheiner Markus Meissner Boris Striepen Brian J. Smith Christopher J. Tonkin
author_sort	Melanie J. Williams
title	Two Essential Light Chains Regulate the MyoA Lever Arm To Promote <italic toggle="yes">Toxoplasma</italic> Gliding Motility
title_short	Two Essential Light Chains Regulate the MyoA Lever Arm To Promote <italic toggle="yes">Toxoplasma</italic> Gliding Motility
title_full	Two Essential Light Chains Regulate the MyoA Lever Arm To Promote <italic toggle="yes">Toxoplasma</italic> Gliding Motility
title_fullStr	Two Essential Light Chains Regulate the MyoA Lever Arm To Promote <italic toggle="yes">Toxoplasma</italic> Gliding Motility
title_full_unstemmed	Two Essential Light Chains Regulate the MyoA Lever Arm To Promote <italic toggle="yes">Toxoplasma</italic> Gliding Motility
title_sort	two essential light chains regulate the myoa lever arm to promote <italic toggle="yes">toxoplasma</italic> gliding motility
publisher	American Society for Microbiology
publishDate	2015
url	https://doaj.org/article/d0c460df28c34814998e886ac78c3a7f
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Two Essential Light Chains Regulate the MyoA Lever Arm To Promote <italic toggle="yes">Toxoplasma</italic> Gliding Motility

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