title: Chkl binds and phosphorylates BAD protein.
abstract: Chk1 (checkpoint kinase 1) is a serine-threonine kinase that is critical for G2/M arrest in response to DNA damage. Chk1 phosphorylates Cdc25C at serine-216, a major regulatory site, in response to DNA damage. Furthermore, Chk1 also phosphorylates Cdc25A on serine 123 which accelerates its degradation through the ubiquitin-proteasome pathway and arrests cells in late G2-phase after DNA damage. In the present study, we demonstrated that Chk1 phosphorylates pro-apoptotic protein BAD (Bcl-2/Bcl-XL-Antagonist, causing cell Death) in vitro. In vitro phosphorylation analysis with various mouse BAD peptides has revealed two phosphorylation sites for Chk1 at serine-155 and serine-170. When wild-type and mutant BAD (S155A) constructs were transfected into 293T cells, an association between BAD and Chk1 was observed by co-immunoprecipitation. In addition, there was an increase in the phosphorylation of serine-155 following DNA damage by adriamycin treatment. Our results suggest that Chk1 associates with BAD and phosphorylates the BAD protein at serine-155. Taken together, our results suggest that Chk1 may inactivate BAD by associating with and phosphorylating residues critical for BAD function in response to DNA damage.
authors.affiliation: Department R47S, AP9A, Cancer Research, Global Pharmaceutical Research Division, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064, USA. edward.k.han@abbott.com
authors.forename: Edward Kyu-ho
authors.initials: EK
authors.lastname: Han
authors.forename: Chris
authors.initials: C
authors.lastname: Butler
authors.forename: Haichao
authors.initials: H
authors.lastname: Zhang
authors.forename: Jean M
authors.initials: JM
authors.lastname: Severin
authors.forename: Wenying
authors.initials: W
authors.lastname: Qin
authors.forename: Tom F
authors.initials: TF
authors.lastname: Holzman
authors.forename: Earl J
authors.initials: EJ
authors.lastname: Gubbins
authors.forename: Robert L
authors.initials: RL
authors.lastname: Simmer
authors.forename: Saul
authors.initials: S
authors.lastname: Rosenberg
authors.forename: Vincent L
authors.initials: VL
authors.lastname: Giranda
authors.forename: Shi-Chung
authors.initials: SC
authors.lastname: Ng
authors.forename: Y
authors.initials: Y
authors.lastname: Luo
mesh_terms: D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D000071877:Checkpoint Kinase 1; D004622:Embryo, Mammalian; D006801:Humans; D007668:Kidney / Q000166:cytology; D008969:Molecular Sequence Data; D011106:Polyisoprenyl Phosphates; D011485:Protein Binding; D011494:Protein Kinases / Q000378:metabolism*; D051025:bcl-Associated Death Protein
chemical_list: C494819:BAD protein, human; D002352:Carrier Proteins; D011106:Polyisoprenyl Phosphates; D051025:bcl-Associated Death Protein; C105485:phosprenyl; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C000605869:Chek1 protein, mouse