Functions in initiation of replication. Key substrate of CDK, phosphorylation promotes interaction with Dpb11, required for initiation of replication in S. cerevisiae (1) (2)

Higher eukaryotic orthologue not identified.





Molecular weight

77 kDa (Sc)

Biochemical properties




Protein interactions


•Cdc45 genetic and 2 hybrid, (3)

•Dbp11  needed for Dbp11 chromatin binding (3) (1) helped by cdc45 (2)

•Mcm2-7 (4)

•GINS (5)



•Cdc45 – (6)


•Phosphorylation (CDK), 12 sites but 2 seem more important (6) (1) (2)



Cellular location and expression


•Interacts with origins (3) and codependence for binding with cdc45 (6)

•Required for initiation but not present at replication forks (ie not required for elongation) (4)



•Binds prior to Cut5, Drc1, GINS and Cdc45 in step that is dependent on DDK but not CDK (7)


Other comments

•Higher eukaryotic orthologue not identified.

Revised by


Last edited

13 April 08



1.    Zegerman,P. and Diffley,J.F. (2007) Phosphorylation of Sld2 and Sld3 by cyclin-dependent kinases promotes DNA replication in budding yeast. Nature 445, 281-285.

2.    Tanaka,S., Umemori,T., Hirai,K., Muramatsu,S., Kamimura,Y. and Araki,H. (2007) CDK-dependent phosphorylation of Sld2 and Sld3 initiates DNA replication in budding yeast. Nature 445, 328-332.

3.    Kamimura,Y., Tak,Y.S., Sugino,A. and Araki,H. (2001) Sld3, which interacts with Cdc45 (Sld4), functions for chromosomal DNA replication in Saccharomyces cerevisiae. EMBO J 20, 2097-2107.

4.    Kanemaki,M. and Labib,K. (2006) Distinct roles for Sld3 and GINS during establishment and progression of eukaryotic DNA replication forks. EMBO J 25, 1753-1763.

5.    Takayama,Y., Kamimura,Y., Okawa,M., Muramatsu,S., Sugino,A. and Araki,H. (2003) GINS, a novel multiprotein complex required for chromosomal DNA replication in budding yeast. Genes Dev 17, 1153-1165.

6.    Nakajima,R. and Masukata,H. (2002) SpSld3 is required for loading and maintenance of SpCdc45 on chromatin in DNA replication in fission yeast. Mol Biol Cell 13, 1462-1472.

7.    Yabuuchi,H., Yamada,Y., Uchida,T., Sunathvanichkul,T., Nakagawa,T. and Masukata,H. (2006) Ordered assembly of Sld3, GINS and Cdc45 is distinctly regulated by DDK and CDK for activation of replication origins. EMBO J 25, 4663-4674.