title: Conformational Change of Human Checkpoint Kinase 1 (Chk1) Induced by DNA Damage.
abstract: Phosphorylation of Chk1 by ataxia telangiectasia-mutated and Rad3-related (ATR) is critical for checkpoint activation upon DNA damage. However, how phosphorylation activates Chk1 remains unclear. Many studies suggest a conformational change model of Chk1 activation in which phosphorylation shifts Chk1 from a closed inactive conformation to an open active conformation during the DNA damage response. However, no structural study has been reported to support this Chk1 activation model. Here we used FRET and bimolecular fluorescence complementary techniques to show that Chk1 indeed maintains a closed conformation in the absence of DNA damage through an intramolecular interaction between a region (residues 31-87) at the N-terminal kinase domain and the distal C terminus. A highly conserved Leu-449 at the C terminus is important for this intramolecular interaction. We further showed that abolishing the intramolecular interaction by a Leu-449 to Arg mutation or inducing ATR-dependent Chk1 phosphorylation by DNA damage disrupts the closed conformation, leading to an open and activated conformation of Chk1. These data provide significant insight into the mechanisms of Chk1 activation during the DNA damage response.
authors.affiliation: From the Department of Pharmacology, Case Comprehensive Cancer Center, and.
authors.forename: Xiangzi
authors.initials: X
authors.lastname: Han
authors.affiliation: the Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou 510632, China.
authors.forename: Jinshan
authors.initials: J
authors.lastname: Tang
authors.affiliation: From the Department of Pharmacology, Case Comprehensive Cancer Center, and.
authors.forename: Jingna
authors.initials: J
authors.lastname: Wang
authors.affiliation: From the Department of Pharmacology, Case Comprehensive Cancer Center, and.
authors.forename: Feng
authors.initials: F
authors.lastname: Ren
authors.affiliation: From the Department of Pharmacology, Case Comprehensive Cancer Center, and.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio 44106 and.
authors.forename: Megan
authors.initials: M
authors.lastname: Gragg
authors.affiliation: From the Department of Pharmacology, Case Comprehensive Cancer Center, and.
authors.forename: Philip
authors.initials: P
authors.lastname: Kiser
authors.affiliation: Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio 44106 and.
authors.forename: Paul S H
authors.initials: PS
authors.lastname: Park
authors.affiliation: From the Department of Pharmacology, Case Comprehensive Cancer Center, and.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Palczewski
authors.affiliation: the Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou 510632, China.
authors.forename: Xinsheng
authors.initials: X
authors.lastname: Yao
authors.affiliation: From the Department of Pharmacology, Case Comprehensive Cancer Center, and yxz169@case.edu.
authors.forename: Youwei
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D002460:Cell Line; D000071877:Checkpoint Kinase 1; D004249:DNA Damage; D031541:Fluorescence Resonance Energy Transfer; D057809:HEK293 Cells; D006801:Humans; D010766:Phosphorylation; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D011494:Protein Kinases / Q000737:chemistry* / Q000378:metabolism
chemical_list: D011494:Protein Kinases; D000071877:Checkpoint Kinase 1
keywords: DNA damage; checkpoint control; molecular cell biology; phosphorylation; protein conformation