6q2a

Publication Abstract from PubMed

The kinetochore is a macromolecular structure that assembles on the centromeres of chromosomes and provides the major attachment point for spindle microtubules during mitosis. In Trypanosoma brucei, the proteins that make up the kinetochore are highly divergent; the inner kinetochore comprises at least 20 distinct and essential proteins (KKT1-20) that include four protein kinases-CLK1 (also known as KKT10), CLK2 (also known as KKT19), KKT2 and KKT3. Here, we report the identification and characterization of the amidobenzimidazoles (AB) protein kinase inhibitors that show nanomolar potency against T. brucei bloodstream forms, Leishmania and Trypanosoma cruzi. We performed target deconvolution analysis using a selection of 29 T. brucei mutants that overexpress known essential protein kinases, and identified CLK1 as a primary target. Biochemical studies and the co-crystal structure of CLK1 in complex with AB1 show that the irreversible competitive inhibition of CLK1 is dependent on a Michael acceptor forming an irreversible bond with Cys 215 in the ATP-binding pocket, a residue that is not present in human CLK1, thereby providing selectivity. Chemical inhibition of CLK1 impairs inner kinetochore recruitment and compromises cell-cycle progression, leading to cell death. This research highlights a unique drug target for trypanosomatid parasitic protozoa and a new chemical tool for investigating the function of their divergent kinetochores.

Targeting the trypanosome kinetochore with CLK1 protein kinase inhibitors.,Saldivia M, Fang E, Ma X, Myburgh E, Carnielli JBT, Bower-Lepts C, Brown E, Ritchie R, Lakshminarayana SB, Chen YL, Patra D, Ornelas E, Koh HXY, Williams SL, Supek F, Paape D, McCulloch R, Kaiser M, Barrett MP, Jiricek J, Diagana TT, Mottram JC, Rao SPS Nat Microbiol. 2020 Jul 13. pii: 10.1038/s41564-020-0745-6. doi:, 10.1038/s41564-020-0745-6. PMID:32661312^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.