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Activation loop phosphorylation and cGMP saturation of PKG regulate egress of malaria parasites

ABSTRACT: The cGMP-dependent protein kinase (PKG) is the sole cGMP sensor in malaria parasites, acting as an essential signalling hub to govern key developmental processes throughout the parasite life cycle. Despite the importance of PKG in the clinically relevant asexual blood stages, many aspects of malarial PKG regulation remain poorly understood. Here we use genetic and biochemical approaches to show that reduced cGMP binding to cyclic nucleotide binding domain B does not affect in vitro kinase activity but prevents parasite egress. Similarly, we show that phosphorylation of a key threonine residue (T695) in the activation loop is dispensable for kinase activity in vitro but is essential for in vivo PKG function, with loss of T695 phosphorylation leading to aberrant phosphorylation events across the parasite proteome and changes to the substrate specificity of PKG. Our findings indicate that Plasmodium PKG is uniquely regulated to transduce signals necessary for malaria parasite development.

INSTRUMENT(S): Orbitrap Eclipse

ORGANISM(S): Plasmodium Falciparum (isolate 3d7)

DISEASE(S): Plasmodium Falciparum Malaria

SUBMITTER: Helen Flynn

LAB HEAD: Mark Skehel

PROVIDER: PXD049017 | Pride | 2024-06-24

REPOSITORIES: Pride

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			Action	DRS
	BG2984_LC_researchTMTPro18_txt.zip	Other
	BG2984_LC_txt.zip	Other
	BG2984_MC1_txt.zip	Other
	BG2984_MC2txt.zip	Other
	BG2984_SMOAC_bRP_txt.zip	Other

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Activation loop phosphorylation and cGMP saturation of PKG regulate egress of malaria parasites

Project description:The cGMP-dependent protein kinase (PKG) is the sole cGMP sensor in malaria parasites, acting as an essential signalling hub to govern key developmental processes throughout the parasite life cycle. Despite the importance of PKG in the clinically relevant asexual blood stages, many aspects of malarial PKG regulation remain poorly understood. Here we use genetic and biochemical approaches to show that reduced cGMP binding to cyclic nucleotide binding domain B does not affect in vitro kinase activity but prevents parasite egress. Similarly, we show that phosphorylation of a key threonine residue (T695) in the activation loop is dispensable for kinase activity in vitro but is essential for in vivo PKG function, with loss of T695 phosphorylation leading to aberrant phosphorylation events across the parasite proteome and changes to the substrate specificity of PKG. Our findings indicate that Plasmodium PKG is uniquely regulated to transduce signals necessary for malaria parasite development.

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