@article{6286fb221fd443faaf57f1bb90be04f4,
title = "Non-catalytic function for ATR in the checkpoint response",
abstract = "The ATR family of checkpoint kinases is essential for an appropriate response to genomic insults in eukaryotes. Included in this family are Mei-41 in Drosophila, Mec1 in S. cerevisiae, Rad3 in S. pombe, and ATR in vertebrates. These large kinases phosphorylate and modify multiple cell cycle and checkpoint factors, leading to cell cycle arrest, DNA repair, and induction of apoptosis. The catalytic domain of all ATR family members comprises only a fraction of the total protein. Here, we show that the non-catalytic portion of ATR has a conserved function in the checkpoint response. Expression of either wild type or various kinase defective forms of Xenopus ATR (XATR) in S. cerevisiae mec1 mutants suppresses the checkpoint defect and induces a DNA damage dependent mitotic cell cycle arrest. This suppression requires the presence of yeast Ddc2 and Rad9 but functions independently of Rad9 modification and Rad53 activation. Our results indicate that XATR is not functioning through the established mitotic checkpoint pathways. Instead, we find that the XATR suppression of the mec1 mutant checkpoint defect requires the spindle checkpoint factors Mad1 and Mad2, suggesting a role for XATR in the spindle assembly checkpoint. Finally, we show that a yeast strain expressing a truncated, kinase domain deleted form of mec1 from the endogenous locus is partially checkpoint proficient and induces a mitotic cell cycle arrest in a Mad2 dependent manner. Thus, the link between the non-catalytic region of the ATR kinase family and the spindle checkpoint pathway is conserved.",
keywords = "ATR, Cell cycle, Checkpoint, PIKK, S. cerevisiae, Spindle assembly, Xenopus, Yeast, mec1",
author = "McSherry, {Troy D.} and Kitazono, {Ana A.} and Ali Javaheri and Kron, {Stephen J.} and Mueller, {Paul R.}",
note = "Funding Information: Xenopus, S. cerevisiae, checkpoint, ATR, mec1, PIKK, spindle assembly, cell cycle, yeast During each eukaryotic cell division, a series of complex biochemical processes are faithfully executed to ensure that an exact copy of the genome is passed to the next generation. Commonly, the precise replication and segregation of the genome occurs in the presence of genomic insults. This results in DNA damage and replication blocks that must be dealt with quickly and efficiently for the normal cell division process to continue. We thank Drs. Phil Carpenter, Steve Accordingly, eukaryotic organisms rely on complex signal transduction pathways termed Elledge, Maria Pia Longhese, Thomas Petes, cell cycle checkpoints. Checkpoints transiently halt cell cycle progression in the face of and Katsunori Sugimoto for gifts of reagents damaged or unreplicated DNA and coordinate DNA repair. Thus, checkpoints ensure that and members of the Mueller lab for crit-the cell cycle progresses appropriately and that damaged DNA is either repaired or the cell ical reading of this manuscript. This work containing the damaged DNA is removed from the population in an organized manner. was supported by National Institutes of The importance of these pathways is highlighted by the link between cell cycle checkpoint Health RO1 grants CA84007 to P.R.M. and defects and cancer-prone genetic diseases.1,2 GM60443 to S.J.K., a translational research Phosphoinositide 3-kinase related kinases (PIKKs) are key components of the DNA grant from the Ludwig Institute for Cancer damage checkpoint pathway. Checkpoint PIKKs are a conserved family of kinases Research to P.R.M. and S.J.K., an AHA characterized by the presence of a carboxyl-terminal phosphoinositide 3-kinase related Greater Midwest predoctoral award to A.J., catalytic domain. However, these kinases are not lipid kinases, but serine/threonine an LLS Scholar grant to S.J.K. and a Kimmel protein kinases.3 In the yeast S. cerevisiae, the checkpoint PIKK homologs are Mec1 and Scholar grant to P.R.M. from the Sidney Tel1. These PIKKs are essential for proper checkpoint response to DNA damage and Kimmel Foundation for Cancer Research. DNA replication inhibition.4 In metazoans, three PIKKs, ATM, ATR, and DNA-PK, {\textcopyright}2007 LANDES BIOSCIENCEhave important roles in processing the checkpoint response. ATM plays a central role in responding to double stranded DNA breaks (DSBs), while ATR is a principal component in the checkpoint response to UV-induced genomic damage and DNA replication inhibi-tion. Although DNA-PK is linked chiefly with DNA repair functions, this PIKK also has a role in the DNA damage checkpoint response.5-7 One of the means of regulating the checkpoint PIKKs is through their interactions with associated cofactors. For example, DNA-PK and ATM are regulated through inter-actions with Ku and Nbs1, respectively.8-11 An essential cofactor of ATR function is",
year = "2007",
month = aug,
day = "15",
doi = "10.4161/cc.6.16.4553",
language = "English",
volume = "6",
pages = "2019--2030",
journal = "Cell Cycle",
issn = "1538-4101",
number = "16",
}