scholarly journals The Human Homologue of Bub3 Is Required for Kinetochore Localization of Bub1 and a Mad3/Bub1-related Protein Kinase

1998 ◽  
Vol 142 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Stephen S. Taylor ◽  
Edward Ha ◽  
Frank McKeon
Keyword(s):  
Protein Kinase ◽  
Mammalian Cells ◽  
Cell Cycle Checkpoint ◽  
Deletion Mapping ◽  
Related Protein ◽  
Checkpoint Control ◽  
Human Homologue ◽  
Checkpoint Response ◽  
Cycle Checkpoint ◽  
Murine Homologue

A feedback control mechanism, or cell cycle checkpoint, delays the onset of anaphase until all the chromosomes are correctly aligned on the mitotic spindle. Previously, we showed that the murine homologue of Bub1 is not only required for checkpoint response to spindle damage, but also restrains progression through a normal mitosis (Taylor, S.S., and F. McKeon. 1997. Cell. 89:727–735). Here, we describe the identification of a human homologue of Bub3, a 37-kD protein with four WD repeats. Like Bub1, Bub3 localizes to kinetochores before chromosome alignment. In addition, Bub3 and Bub1 interact in mammalian cells. Deletion mapping was used to identify the domain of Bub1 required for binding Bub3. Significantly, this same domain is required for kinetochore localization of Bub1, suggesting that the role of Bub3 is to localize Bub1 to the kinetochore, thereby activating the checkpoint in response to unattached kinetochores. The identification of a human Mad3/Bub1-related protein kinase, hBubR1, which can also bind Bub3 in mammalian cells, is described. Ectopically expressed hBubR1 also localizes to kinetochores during prometaphase, but only when hBub3 is overexpressed. We discuss the implications of the common interaction between Bub1 and hBubR1 with hBub3 for checkpoint control.

scholarly journals Protein kinase mutants of human ATR increase sensitivity to UV and ionizing radiation and abrogate cell cycle checkpoint control

1998 ◽  
Vol 95 (13) ◽  
pp. 7445-7450 ◽  
Author(s):  
J. A. Wright ◽  
K. S. Keegan ◽  
D. R. Herendeen ◽  
N. J. Bentley ◽  
A. M. Carr ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Ionizing Radiation ◽  
Cell Cycle Checkpoint ◽  
Checkpoint Control ◽  
Cycle Checkpoint

DNA damage checkpoint kinases in cancer

2020 ◽  
Vol 22 ◽  
Author(s):  
Hannah L. Smith ◽  
Harriet Southgate ◽  
Deborah A. Tweddle ◽  
Nicola J. Curtin
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Environmental Dna ◽  
Cell Cycle Checkpoint ◽  
Checkpoint Control ◽  
Integrated Network ◽  
Checkpoint Kinases ◽  
G1 Checkpoint ◽  
Cycle Checkpoint ◽  
High Level

Abstract DNA damage response (DDR) pathway prevents high level endogenous and environmental DNA damage being replicated and passed on to the next generation of cells via an orchestrated and integrated network of cell cycle checkpoint signalling and DNA repair pathways. Depending on the type of damage, and where in the cell cycle it occurs different pathways are involved, with the ATM-CHK2-p53 pathway controlling the G1 checkpoint or ATR-CHK1-Wee1 pathway controlling the S and G2/M checkpoints. Loss of G1 checkpoint control is common in cancer through TP53, ATM mutations, Rb loss or cyclin E overexpression, providing a stronger rationale for targeting the S/G2 checkpoints. This review will focus on the ATM-CHK2-p53-p21 pathway and the ATR-CHK1-WEE1 pathway and ongoing efforts to target these pathways for patient benefit.

scholarly journals Xenopus Cds1 Is Regulated by DNA-Dependent Protein Kinase and ATR during the Cell Cycle Checkpoint Response to Double-Stranded DNA Ends

2004 ◽  
Vol 24 (22) ◽  
pp. 9968-9985 ◽  
Author(s):  
Troy D. McSherry ◽  
Paul R. Mueller
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Cell Cycle Checkpoint ◽  
Dual Function ◽  
Dependent Protein Kinase ◽  
Double Stranded Dna ◽  
Cycle Checkpoint ◽  
Protein Dissociation ◽  
Dependent Protein ◽  
Dna Ends

ABSTRACT The checkpoint kinase Cds1 (Chk2) plays a key role in cell cycle checkpoint responses with functions in cell cycle arrest, DNA repair, and induction of apoptosis. Proper regulation of Cds1 is essential for appropriate cellular responses to checkpoint-inducing insults. While the kinase ATM has been shown to be important in the regulation of human Cds1 (hCds1), here we report that the kinases ATR and DNA-dependent protein kinase (DNA-PK) play more significant roles in the regulation of Xenopus Cds1 (XCds1). Under normal cell cycle conditions, nonactivated XCds1 constitutively associates with a Xenopus ATR complex. The association of XCds1 with this complex does not require a functional forkhead activation domain but does require a putative SH3 binding region that is found in XCds1. In response to double-stranded DNA ends, the amino terminus of XCds1 is rapidly phosphorylated in a sequential pattern. First DNA-PK phosphorylates serine 39, a site not previously recognized as important in Cds1 regulation. Xenopus ATM, ATR, and/or DNA-PK then phosphorylate three consensus serine/glutamine sites. Together, these phosphorylations have the dual function of inducing dissociation from the ATR complex and independently promoting the full activation of XCds1. Thus, the checkpoint-mediated activation of XCds1 requires phosphorylation by multiple phosphoinositide 3-kinase-related kinases, protein-protein dissociation, and autophosphorylation.

scholarly journals Undamaged DNA Transmits and Enhances DNA Damage Checkpoint Signals in Early Embryos

2007 ◽  
Vol 27 (19) ◽  
pp. 6852-6862 ◽  
Author(s):  
Aimin Peng ◽  
Andrea L. Lewellyn ◽  
James L. Maller
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Nuclear Dna ◽  
Cell Cycle Checkpoint ◽  
Dna Damage Checkpoint ◽  
Checkpoint Signaling ◽  
Checkpoint Response ◽  
Egg Extracts ◽  
Cycle Checkpoint ◽  
Damaged Dna

ABSTRACT In Xenopus laevis embryos, the midblastula transition (MBT) at the 12th cell division marks initiation of critical developmental events, including zygotic transcription and the abrupt inclusion of gap phases into the cell cycle. Interestingly, although an ionizing radiation-induced checkpoint response is absent in pre-MBT embryos, introduction of a threshold amount of undamaged plasmid or sperm DNA allows a DNA damage checkpoint response to be activated. We show here that undamaged threshold DNA directly participates in checkpoint signaling, as judged by several dynamic changes, including H2AX phosphorylation, ATM phosphorylation and loading onto chromatin, and Chk1/Chk2 phosphorylation and release from nuclear DNA. These responses on physically separate threshold DNA require γ-H2AX and are triggered by an ATM-dependent soluble signal initiated by damaged DNA. The signal persists in egg extracts even after damaged DNA is removed from the system, indicating that the absence of damaged DNA is not sufficient to end the checkpoint response. The results identify a novel mechanism by which undamaged DNA enhances checkpoint signaling and provide an example of how the transition to cell cycle checkpoint activation during development is accomplished by maternally programmed increases in the DNA-to-cytoplasm ratio.

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