Phosphorylation of human DNA polymerase lambda by the cyclin-dependent kinase Cdk2/cyclin A complex is modulated by its association with proliferating cell nuclear antigen.
DNA polymerase (Pol) lambda is a member of the Pol X family and possesses four different enzymatic activities, being DNA polymerase, terminal transferase, deoxyribose phosphate lyase and polynucleotide synthetase, all localized in its C-terminal region. On the basis of its biochemical properties, Pol lambda has been implicated in various DNA repair pathways, such as abasic site translesion DNA synthesis, base excision repair and non-homologous end joining of double strand breaks. However, its role in vivo has not yet been elucidated. In addition, Pol lambda has been shown to interact with the replication clamp proliferating cell nuclear antigen (PCNA) in vitro and in vivo. In this work, we searched by affinity chromatography for novel partners and we identified the cyclin-dependent kinase Cdk2 as novel partner of Pol lambda. Pol lambda is phosphorylated in vitro by several Cdk/cyclin complexes, including Cdk2/cyclin A, in its proline-serine-rich domain. While the polymerase activity of Pol lambda was not affected by Cdk2/cyclin A phosphorylation, phosphorylation of Pol lambda was decreased by its interaction with PCNA. Finally, Pol lambda is also phosphorylated in vivo in human cells and this phosphorylation is modulated during the cell cycle.
Frouin
Isabelle
I
Institute of Veterinary Biochemistry and Molecular Biology, University of Zürich-Irchel Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
Toueille
Magali
M
Ferrari
Elena
E
Shevelev
Igor
I
Hübscher
Ulrich
U
D000595:Amino Acid Sequence; D016203:CDC2 Protein Kinase / Q000378:metabolism; D042846:CDC2-CDC28 Kinases / Q000378:metabolism*; D002453:Cell Cycle; D019925:Cyclin A / Q000378:metabolism*; D019927:Cyclin E / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D019951:DNA Polymerase beta / Q000737:chemistry / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D010766:Phosphorylation; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D011392:Proline / Q000032:analysis; D017434:Protein Structure, Tertiary; D012694:Serine / Q000032:analysis
D019925:Cyclin A; D019927:Cyclin E; D018809:Proliferating Cell Nuclear Antigen; D012694:Serine; D011392:Proline; D016203:CDC2 Protein Kinase; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; C415367:DNA polymerase beta2; D019951:DNA Polymerase beta