Genotoxin-induced Rad9-Hus1-Rad1 (9-1-1) chromatin association is an early checkpoint signaling event

A1 Journal article (refereed)

Internal Authors/Editors

Publication Details

List of Authors: Roos-Mattjus P, Vroman BT, Burtelow MA, Rauen M, Eapen AK, Karnitz LM
Publication year: 2002
Journal: Journal of Biological Chemistry
Journal acronym: J BIOL CHEM
Volume number: 277
Issue number: 46
Start page: 43809
End page: 43812
Number of pages: 4
ISSN: 0021-9258
eISSN: 1083-351X


Rad17, Rad1, Hus1, and Rad9 are key participants in checkpoint signaling pathways that block cell cycle progression in response to genotoxins. Biochemical and molecular modeling data predict that Rad9, Hus1, and Rad1 form a heterotrimeric complex, dubbed 9-1-1, which is loaded onto chromatin by a complex of Rad17 and the four small replication factor C (RFC) subunits (Rad17-RFC) in response to DNA damage. It is unclear what checkpoint proteins or checkpoint signaling events regulate the association of the 9-1-1 complex with DNA. Here we show that genotoxin-induced chromatin binding of 9-1-1 does not require the Rad9-inducible phosphorylation site (Ser-272). Although we found that Rad9 undergoes an additional phosphatidylinositol 3-kinase-related kinase (PIKK)-dependent posttranslational modification, we also show that genotoxin-triggered 9-1-1 chromatin binding does not depend on the catalytic activity of the PIKKs ataxia telangiectasia-mutated (ATM), ataxia telangiectasia and Rad3-related (ATR), or DNA-PK. Additionally, 9-1-1 chromatin binding does not require DNA replication, suggesting that the complex can be loaded onto DNA in response to DNA structures other than stalled DNA replication forks. Collectively, these studies demonstrate that 9-1-1 chromatin binding is a proximal event in the checkpoint signaling cascade.

Last updated on 2020-28-03 at 04:00