Broad Institute Identification of malaria Hsp40 chaperone inhibitors in yeast Inhibitor Probe Project
The assay provider laboratory has used yeast to model the cellular defects caused by the human proteins implicated in neurodegenerative diseases. Furthermore, we have studied the reliance of fungal pathogens on the protein folding machinery to evolve drug resistance. Recently, we have begun to apply the lessons we learned from these two research areas to the investigation of the malaria pathogen more ..
Susan Lindquist, Whitehead Institute, Cambridge, MA, firstname.lastname@example.org,617-258-5184
Lauren Pepper, Whitehead Institute,Cambridge, MA, email@example.com,617-258-5190
Aims and goals specified in corresponding grant
1. Identification of small molecules that inhibit the activity of the Pf HSP40 PFA0660w
2. Elimination of identified small molecules toxic to human cells.
3. Testing the efficacy of identified small molecules on parasites in culture.
4. Mechanism determination using established in vitro chaperon assays.
2.2 Probe attributes:
Biological Characteristics Prior Art Desired Probe
Target Activity NA IC50 < 10 muM in yeast and/or P. Falciparum
Selectivity: Anti-Target name(s) NA > 10X selective over Human HSP40
Biological Mode of Action NA
1. Active in inhibiting growth of P. falciparum in red blood
cells at < 10 uM
2. Inhibiting P. falciparum HSP40 co-chaperon
activity/host HSP70 chaperon activity
Cellular Toxicity NA Non toxic to mammalian cells at 20 uM
Functional Groups to be avoided NA
1. Chemically reactive groups
2. Metabolically labile groups
3. pH sensitive or hydrolytically unstable groups
Chemical Solubility Criteria NA Soluble in aqueous buffer
The assay provider laboratory has used yeast to model the cellular defects caused by the human proteins implicated in neurodegenerative diseases. Furthermore, we have studied the reliance of fungal pathogens on the protein folding machinery to evolve drug resistance. Recently, we have begun to apply the lessons we learned from these two research areas to the investigation of the malaria pathogen Plasmodium falciparum. The genome of P. falciparum is very AT-rich and consequently encodes an unusual amount of asparagine-rich proteins, predicted to be non-globular and of low complexity and thus likely to impose unique demands on the protein folding machinery. Strikingly, P. falciparum also shows a marked expansion of the heat shock protein 40 (Hsp40) family of co-chaperons. During its life cycle in its human host P. falciparum infects and remodels red blood cells. We propose that during this process the parasite relies on a greatly expanded class of Hsp40 co-chaperons. We have developed assays to assess the function of Pf Hsp40s in yeast and we seek to identify small molecules that inhibit the functions of those chaperons. In particular we focus on a Pf Hsp40 that has been shown to be crucial to parasite proliferation. Compounds inhibiting the function of this Hsp40 in yeast will be tested in established parasite survival and host cell remodeling assays to elucidate the role of this Hsp40 in the parasite life cycle.