Identification and Functional Characterisation of CRK12:CYC9, a Novel Cyclin-Dependent Kinase (CDK)-Cyclin Complex in Trypanosoma brucei

• Published in: PloS one 2013-06, Vol.8 (6), p.e67327-e67327
• Main Authors: Monnerat, Séverine, Almeida Costa, Cristina I, Forkert, Andrea C, Benz, Corinna, Hamilton, Alana, Tetley, Laurence, Burchmore, Richard, Novo, Carlos, Mottram, Jeremy C, Hammarton, Tansy C
• Format: Article
• Language: English
• Subjects: Animals; Biology; Cdc2 protein; Cell cycle; Cell Proliferation - genetics; Cyclin-dependent kinase; Cyclin-dependent kinases; Cyclins; Cyclins - genetics; Cyclins - metabolism; Cytokinesis; Endocytosis; Eukaryotes; Gene expression; Infections; Inflammation; Kinases; Life cycle engineering; Life cycles; Medicine; Mice; Multiprotein Complexes - genetics; Multiprotein Complexes - metabolism; Parasitology; Protein kinase; Protein kinase C; Protein kinases; Proteins; Proto-Oncogene Proteins c-crk - genetics; Proto-Oncogene Proteins c-crk - metabolism; Protozoa; Protozoan Proteins - genetics; Protozoan Proteins - metabolism; Ribonucleic acid; RNA; RNA polymerase; RNA-mediated interference; Transcription; Trypanosoma brucei; Trypanosoma brucei brucei - genetics; Trypanosoma brucei brucei - metabolism; Trypanosomiasis; Trypanosomiasis, African - genetics; Trypanosomiasis, African - metabolism; Vector-borne diseases
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0067327

The protozoan parasite, Trypanosoma brucei, is spread by the tsetse fly and causes trypanosomiasis in humans and animals. Both the life cycle and cell cycle of the parasite are complex. Trypanosomes have eleven cdc2-related kinases (CRKs) and ten cyclins, an unusually large number for a single celled organism. To date, relatively little is known about the function of many of the CRKs and cyclins, and only CRK3 has previously been shown to be cyclin-dependent in vivo. Here we report the identification of a previously uncharacterised CRK:cyclin complex between CRK12 and the putative transcriptional cyclin, CYC9. CRK12:CYC9 interact to form an active protein kinase complex in procyclic and bloodstream T. brucei. Both CRK12 and CYC9 are essential for the proliferation of bloodstream trypanosomes in vitro, and we show that CRK12 is also essential for survival of T. brucei in a mouse model, providing genetic validation of CRK12:CYC9 as a novel drug target for trypanosomiasis. Further, functional characterisation of CRK12 and CYC9 using RNA interference reveals roles for these proteins in endocytosis and cytokinesis, respectively.