Friday, May 28, 2010

Toxoplasma gondii calcium-dependent protein kinase 1 is a target for selective kinase inhibitors

Nat Struct Mol Biol. 2010 May;17(5):602-7. Epub 2010 May 2.

Toxoplasma gondii calcium-dependent protein kinase 1 is a target for selective kinase inhibitors

Ojo KK, Larson ET, Keyloun KR, Castaneda LJ, Derocher AE, Inampudi KK, Kim JE, Arakaki TL, Murphy RC, Zhang L, Napuli AJ, Maly DJ, Verlinde CL, Buckner FS, Parsons M, Hol WG, Merritt EA, Van Voorhis WC.

Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, USA.

Abstract
New drugs are needed to treat toxoplasmosis. Toxoplasma gondii calcium-dependent protein kinases (TgCDPKs) are attractive targets because they are absent in mammals. We show that TgCDPK1 is inhibited by low nanomolar levels of bumped kinase inhibitors (BKIs), compounds inactive against mammalian kinases. Cocrystal structures of TgCDPK1 with BKIs confirm that the structural basis for selectivity is due to the unique glycine gatekeeper residue in the ATP-binding site. We show that BKIs interfere with an early step in T. gondii infection of human cells in culture. Furthermore, we show that TgCDPK1 is the in vivo target of BKIs because T. gondii expressing a glycine to methionine gatekeeper mutant enzyme show significantly decreased sensitivity to BKIs. Thus, design of selective TgCDPK1 inhibitors with low host toxicity may be achievable.

PMID: 20436472 [PubMed - indexed for MEDLINE]