TY - JOUR
T1 - Chk1-Mad2 interaction
T2 - A crosslink between the DNA damage checkpoint and the mitotic spindle checkpoint
AU - Chilà, Rosaria
AU - Celenza, Cinzia
AU - Lupi, Monica
AU - Damia, Giovanna
AU - Carrassa, Laura
PY - 2013/4/1
Y1 - 2013/4/1
N2 - Chk1 is implicated in several checkpoints of the cell cycle acting as a key player in the signal transduction pathway activated in response to DNA damage and crucial for the maintenance of genomic stability. Chk1 also plays a role in the mitotic spindle checkpoint, which ensures thefidelity of mitotic segregation during mitosis, preventing chromosomal instability and aneuploidy. Mad2 is one of the main mitotic checkpoint components and also exerts a role in the cellular response to DNA damage. To investigate a possible crosslink existing between Chk1 and Mad2, we studied Mad2 protein levels after Chk1 inhibition either by specific siRNAs or by a specific and selective Chk1 inhibitor (PF-00477736), and we found that after Chk1 inhibition, Mad2 protein levels decrease only in tumor cells sensitive to Chk1 depletion. We then mapped six Chk1's phosphorylatable sites on Mad2 protein, and found that Chk1 is able to phosphorylate Mad2 in vitro on more than one site, while it is incapable of phoshorylating the Mad2 form mutated on all six phosphorylatable sites. Moreover our studies demonstrate that Chk1 co-localizes and physically associates with Mad2 in cells both under unstressed conditions and after DNA damage, thus providing new and interesting evidence on Chk1 and Mad2 crosstalk in the DNA damage checkpoint and in the mitotic spindle checkpoint.
AB - Chk1 is implicated in several checkpoints of the cell cycle acting as a key player in the signal transduction pathway activated in response to DNA damage and crucial for the maintenance of genomic stability. Chk1 also plays a role in the mitotic spindle checkpoint, which ensures thefidelity of mitotic segregation during mitosis, preventing chromosomal instability and aneuploidy. Mad2 is one of the main mitotic checkpoint components and also exerts a role in the cellular response to DNA damage. To investigate a possible crosslink existing between Chk1 and Mad2, we studied Mad2 protein levels after Chk1 inhibition either by specific siRNAs or by a specific and selective Chk1 inhibitor (PF-00477736), and we found that after Chk1 inhibition, Mad2 protein levels decrease only in tumor cells sensitive to Chk1 depletion. We then mapped six Chk1's phosphorylatable sites on Mad2 protein, and found that Chk1 is able to phosphorylate Mad2 in vitro on more than one site, while it is incapable of phoshorylating the Mad2 form mutated on all six phosphorylatable sites. Moreover our studies demonstrate that Chk1 co-localizes and physically associates with Mad2 in cells both under unstressed conditions and after DNA damage, thus providing new and interesting evidence on Chk1 and Mad2 crosstalk in the DNA damage checkpoint and in the mitotic spindle checkpoint.
KW - Chk1
KW - DNA damage checkpoint
KW - Mad2
KW - Mitotic spindle checkpoint
UR - http://www.scopus.com/inward/record.url?scp=84875890330&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84875890330&partnerID=8YFLogxK
U2 - 10.4161/cc.24090
DO - 10.4161/cc.24090
M3 - Article
C2 - 23454898
AN - SCOPUS:84875890330
VL - 12
SP - 1083
EP - 1090
JO - Cell Cycle
JF - Cell Cycle
SN - 1538-4101
IS - 7
ER -