Abstract 4793
Background
ATM is an important cell cycle checkpoint kinase. This protein is an controller of cell cycle checkpoint that is required for cell response to DNA damage and for genome stability. The spindle assembly checkpoint (SAC) controls accurate chromosome segregation to maintain genome stability. All kinetochores correctly attach to the spindle, which allow mitosis to proceed. Bub3 is the mainly component of the SAC, in which its kinase activity can stabilize the correct kinetochore–microtubule attachments. Genomic stability is a hallmarks of breast cancer, and the level of Bub3 in breast cancer are higher than that in normal tussue. Understanding how the ATM-Bub3 signal contributes to kinetochore-based signaling may help us to recognize the occurrence of breast cancer.
Methods
Stable Isotope Labeling with Amino Acid in Cell Culture (SILAC) to identify ATM interation protein in breast cancer. Bioinformatics analyze the phosphorylation site of Bub3. Biacore assay and in vitro kinase assay to validate the phosphorylation site. Flow cytometry assay to check the mitotic index. Mutation of the phosphorylation site of bub3 and Co-IP were proformed to identify the interation of Bub3 and Bub1 or ZNF207, and western blot to be used to test the activity of Bub1.
Results
Through Stable Isotope Labeling with Amino Acid in Cell Culture (SILAC), we identified additional mitotic proteins that interact and can be phosphorylated by mitotically activated ATM kinase. We provide both in vitro and in vivo evidence that ATM phosphorylates Bub3 on Serine 135. This phosphorylation event promotes Bub1 activity in the mitotic spindle checkpoint. Further, we find that phosphorylation of Bub3 on Ser135 is required for formation of the Bub3-Bub1 complex, which is essential for Bub1 Ser314 phosphorylation. Mutation of Ser135 to alanine of Bub3 resulted in an enhanced interaction with BuGZ/ZNF207 and reduced interaction with Bub1, which lead to a spindle checkpoint defect.
Conclusions
Our findings highlight the functional significance of ATM-mediated kinetochore protein phosphorylation and elucidate a detailed regulatory mechanism of the SAC in breast cancer.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
4955 - XAF1 Enhances Temozolomide Induced Autophagic Cell Death through AMPK signaling pathway
Presenter: Mingoo Lee
Session: Poster Display session 1
Resources:
Abstract
5616 - The effect of cortisol on methylation patterns in breast cancer cell lines
Presenter: Haya Intabli
Session: Poster Display session 1
Resources:
Abstract
4649 - Global and sex-specific epigenome-wide association studies for the identification of the main methylated loci related to smoking in a Mediterranean population
Presenter: Judith Begona Ramirez Sabio
Session: Poster Display session 1
Resources:
Abstract
4984 - Whole transcriptomics analyses of mimicking Circulating Tumor Cells (CTCs) by single-cell RNA sequencing (scRNAseq)
Presenter: Jessica Garcia
Session: Poster Display session 1
Resources:
Abstract
5926 - Comparison of enzymatic- and bisulfite conversion to map the plasma cell-free methylome in cancer
Presenter: Nicole Lambert
Session: Poster Display session 1
Resources:
Abstract
5454 - Detection of low mutations in hepatocellular carcinoma by using circulating tumor DNA
Presenter: Esl Kim
Session: Poster Display session 1
Resources:
Abstract
4428 - Variants in the JAK1 and JAK2 genes in the risk and prognosis of patients with cutaneous melanoma
Presenter: Bruna Carvalho
Session: Poster Display session 1
Resources:
Abstract
4409 - P-Rex1 expression in breast cancer patients.
Presenter: Angela Lara Montero
Session: Poster Display session 1
Resources:
Abstract
4185 - Modulation of Risk of Cutaneous Melanoma Patients by Variants in STAT3 Gene and Functional Analysis
Presenter: Gabriela Gomez
Session: Poster Display session 1
Resources:
Abstract
3909 - Spectrum of pathogenic germline mutations in Chinese lung cancer patients through next-generation sequencing
Presenter: Ying Huang
Session: Poster Display session 1
Resources:
Abstract