Trypanosoma cruzi Tcp12CKS1 interacts with parasite CRKs and rescues the p13SUC1 fission yeast mutant

The complex mechanism of cell division in trypanosomatids is not completely fully understood. CRKs (cdc2-related kinases), Cyclins and CKSs (cdc2-kinase subunit) are involved in the progression through the cell cycle. The CKS proteins were first described as components of the cell cycle machinery in yeast and their action has been implicated in the regulation of CDK function. In the present work we identified Tcp12CKS1 a member of the CKS family in the parasite Trypanosoma cruzi. TcCKS1 is expressed in the three forms of T. cruzi. By using anti-Tcp12CKS1 antiserum, protein kinase (PK) activities were immunoprecipitated. The PK activity level varies depending on the stage analyzed, being lower in trypomastigotes and thus suggesting that different stages have different CKS–CRK complexes. Moreover, these PK activities were inhibited by using Flavopiridol, a known CDKs inhibitor. Western blot analyses demonstrated that in the epimastigote stage, p12CKS1 stably interacts with TcCRK1 and TcCRK3. In addition, Tcp12CKS1 was able to rescue the p13SUC1 null mutant of S. pombe. The functional complementation between the CKS proteins of two evolutionary distant organisms supports the role of Tcp12CKS1 as a key regulator in T. cruzi cell cycle.