title: Identification of proteases that regulate erythrocyte rupture by the malaria parasite Plasmodium falciparum.
abstract: Newly replicated Plasmodium falciparum parasites escape from host erythrocytes through a tightly regulated process that is mediated by multiple classes of proteolytic enzymes. However, the identification of specific proteases has been challenging. We describe here a forward chemical genetic screen using a highly focused library of more than 1,200 covalent serine and cysteine protease inhibitors to identify compounds that block host cell rupture by P. falciparum. Using hits from the library screen, we identified the subtilisin-family serine protease PfSU B1 and the cysteine protease dipeptidyl peptidase 3 (DPAP3) as primary regulators of this process. Inhibition of both DPAP3 and PfSUB1 caused a block in proteolytic processing of the serine repeat antigen (SERA) protein SERA5 that correlated with the observed block in rupture. Furthermore, DPAP3 inhibition reduced the levels of mature PfSUB1. These results suggest that two mechanistically distinct proteases function to regulate processing of downstream substrates required for efficient release of parasites from host red blood cells.
authors.affiliation: Department of Pathology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, California 94305, USA.
authors.forename: Shirin
authors.initials: S
authors.lastname: Arastu-Kapur
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Ponder
authors.forename: Ursa Pecar
authors.initials: UP
authors.lastname: Fonović
authors.forename: Sharon
authors.initials: S
authors.lastname: Yeoh
authors.forename: Fang
authors.initials: F
authors.lastname: Yuan
authors.forename: Marko
authors.initials: M
authors.lastname: Fonović
authors.forename: Munira
authors.initials: M
authors.lastname: Grainger
authors.forename: Carolyn I
authors.initials: CI
authors.lastname: Phillips
authors.forename: James C
authors.initials: JC
authors.lastname: Powers
authors.forename: Matthew
authors.initials: M
authors.lastname: Bogyo
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000187:drug effects / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000378:metabolism / Q000469:parasitology*; D006790:Host-Parasite Interactions / Q000187:drug effects; D006801:Humans; D049934:Isocoumarins / Q000737:chemistry / Q000494:pharmacology; D016778:Malaria, Falciparum / Q000378:metabolism / Q000469:parasitology*; D008968:Molecular Conformation; D021261:Parasitic Sensitivity Tests; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D011480:Protease Inhibitors / Q000737:chemistry / Q000494:pharmacology; D015800:Protozoan Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D012697:Serine Endopeptidases / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D054852:Small Molecule Libraries; D013237:Stereoisomerism; D013381:Subtilisins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D013450:Sulfones / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000953:Antigens, Protozoan; D049934:Isocoumarins; C531028:JCP 104; C531029:JCP 405; C531030:JCP 410; D010455:Peptides; D011480:Protease Inhibitors; D015800:Protozoan Proteins; D054852:Small Molecule Libraries; D013450:Sulfones; C480167:serine repeat antigen 5, Plasmodium falciparum; D012697:Serine Endopeptidases; D013381:Subtilisins; C403176:subtilisin-like protease 1, Plasmodium falciparum; D003546:Cysteine Endopeptidases