Protein Kinase A Dependent Phosphorylation of Apical Membrane Antigen 1 Plays an Important Role in Erythrocyte Invasion by the Malaria Parasite

Autor: Paul R. Gilson, Tim W. Gilberger, Alan F. Cowman, Moritz Treeck, Thomas Braulke, Brendan S. Crabb, Kerstin Leykauf, Thomas Nebl
Rok vydání: 2010
Předmět:
lcsh:Immunologic diseases. Allergy
Erythrocytes
Immunoprecipitation
Gliding motility
Blotting
Western
Molecular Sequence Data
Plasmodium falciparum
Immunology
Protozoan Proteins
Antigens
Protozoan
Microbiology
Virology
parasitic diseases
Biochemistry/Cell Signaling and Trafficking Structures
Genetics
Humans
Electrophoresis
Gel
Two-Dimensional
Amino Acid Sequence
Microbiology/Parasitology
Malaria
Falciparum
Phosphorylation
Apical membrane antigen 1
Protein kinase A
lcsh:QH301-705.5
Molecular Biology
Sequence Homology
Amino Acid
biology
Intracellular parasite
Infectious Diseases/Protozoal Infections
Membrane Proteins
biology.organism_classification
Cyclic AMP-Dependent Protein Kinases
Recombinant Proteins
Cell biology
lcsh:Biology (General)
Membrane protein
Spectrometry
Mass
Matrix-Assisted Laser Desorption-Ionization
Parasitology
lcsh:RC581-607
Research Article
Zdroj: PLoS Pathogens, Vol 6, Iss 6, p e1000941 (2010)
PLoS Pathogens
ISSN: 1553-7374
DOI: 10.1371/journal.ppat.1000941
Popis: Apicomplexan parasites are obligate intracellular parasites that infect a variety of hosts, causing significant diseases in livestock and humans. The invasive forms of the parasites invade their host cells by gliding motility, an active process driven by parasite adhesion proteins and molecular motors. A crucial point during host cell invasion is the formation of a ring-shaped area of intimate contact between the parasite and the host known as a tight junction. As the invasive zoite propels itself into the host-cell, the junction moves down the length of the parasite. This process must be tightly regulated and signalling is likely to play a role in this event. One crucial protein for tight-junction formation is the apical membrane antigen 1 (AMA1). Here we have investigated the phosphorylation status of this key player in the invasion process in the human malaria parasite Plasmodium falciparum. We show that the cytoplasmic tail of P. falciparum AMA1 is phosphorylated at serine 610. We provide evidence that the enzyme responsible for serine 610 phosphorylation is the cAMP regulated protein kinase A (PfPKA). Importantly, mutation of AMA1 serine 610 to alanine abrogates phosphorylation of AMA1 in vivo and dramatically impedes invasion. In addition to shedding unexpected new light on AMA1 function, this work represents the first time PKA has been implicated in merozoite invasion.
Author Summary The invasion of host cells by zoites of the phylum apicomplexa is an active event that is powered by the parasite invasion machinery. It can be divided in several distinct steps that involve binding to the host cell, reorientation and tight junction formation that are accompanied by sequential secretion of specialised organelles that store proteins involved in these events. A great number of proteins are now known to be involved in invasion but how the invasion process is regulated remains obscure. Recently, phosphorylation of some proteins with a defined function in invasion like GAP45, MTIP and AMA1 were reported and provided the first insight into putative regulation mechanism of invasion. Using mutational analysis we now demonstrate that AMA1 is phosphorylated in the cytoplasmic domain at serine 610 in a cAMP dependent manner and that mutation of S610 dramatically reduces the efficiency of invasion into erythrocytes. We identified protein kinase A (PfPKA) as a late transcribed kinase that is responsible for phosphorylating AMA1 at this specific residue. This work describes for the first time PKA signalling being implicated in merozoite invasion, providing a new avenue for understanding the initiation and regulation of invasion. Significantly also, the PKA-AMA1 pathway defines a promising new and validated drug target for therapeutic intervention.
Databáze: OpenAIRE
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