The CRK2-CYC13 complex functions as an S-phase cyclin-dependent kinase to promote DNA replication in Trypanosoma brucei

• Published in: BMC biology Vol. 19; no. 1; p. 29
• Main Authors: Lee, Kyu Joon, Li, Ziyin
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 11.02.2021; BioMed Central; BMC
• Subjects: Analysis; Cdc2 protein; Cdc2-related kinase; Cdc45 protein; Cdc45-Mcm2–7-GINS complex; Cell cycle; Cell division; Cyclin-dependent kinase; Cyclin-dependent kinases; Deoxyribonucleic acid; DNA; DNA biosynthesis; DNA polymerase; DNA replication; Dosage and administration; Genomes; Identification and classification; Kinases; Mcm3; Microscopy; Observations; Parasites; Phosphorylation; Prevention; Protein kinases; Proteins; Replication; Replication initiation; Sld5; Tetracycline; Tetracyclines; Trypanosoma brucei; Yeast; Yeasts; United States; Mcm3; Cdc45-Mcm2–7-GINS complex; DNA replication; Trypanosoma brucei; Cdc2-related kinase; Sld5
• ISSN: 1741-7007; 1741-7007
• DOI: 10.1186/s12915-021-00961-1

Faithful DNA replication is essential to maintain genomic stability in all living organisms, and the regulatory pathway for DNA replication initiation is conserved from yeast to humans. The evolutionarily ancient human parasite Trypanosoma brucei, however, lacks many of the conserved DNA replication factors and may employ unusual mechanisms for DNA replication. Neither the S-phase cyclin-dependent kinase (CDK) nor the regulatory pathway governing DNA replication has been previously identified in T. brucei. Here we report that CRK2 (Cdc2-related kinase 2) complexes with CYC13 (Cyclin13) and functions as an S-phase CDK to promote DNA replication in T. brucei. We further show that CRK2 phosphorylates Mcm3, a subunit of the Mcm2-7 sub-complex of the Cdc45-Mcm2-7-GINS complex, and demonstrate that Mcm3 phosphorylation by CRK2 facilitates interaction with Sld5, a subunit of the GINS sub-complex of the Cdc45-Mcm2-7-GINS complex. These results identify the CRK2-CYC13 complex as an S-phase regulator in T. brucei and reveal its role in regulating DNA replication through promoting the assembly of the Cdc45-Mcm2-7-GINS complex.