FLJ25439, a novel cytokinesis-associated protein, induces tetraploidization and maintains chromosomal stability via enhancing expression of endoplasmic reticulum stress chaperones.
Investigation of the mechanisms leading to aneuploidy and polyploidy is critical to cancer research. Previous studies have provided strong evidence of the importance of tetraploidization as an early step in tumorigenesis. In cancer cells, tetraploid cells may contribute to abnormal mitotic progression, which may be associated with cytokinesis failure. Tetraploidy leads to genomic instability due to centrosome and chromosome over-replication. Until now, the mechanism by which cells maintain tetraploid status has been unknown. Here, we identified a novel D box-containing protein, FLJ25439, which displays a dynamic expression profile during mitosis/cytokinesis with the midbody as the most prominent associated structure. To understand the function of FLJ25439, we established stable cell lines overexpressing FLJ25439. FLJ25439-overexpression cells grew slower and displayed a tetraploid DNA content in comparison with diploid parental cells. They also showed aberrant mitosis and dysregulated expression of p53, pRb and p21, suggesting a defect in cell cycle progression. To explore the molecular mechanisms responsible for FLJ25439-induced tetraploidization, we conducted a comparative analysis of the global protein expression patterns of wild type and overexpressors using proteomics and bioinformatics approaches. Protein category profiling indicated that FLJ25439 is involved in pathways related to anti-apoptosis, protein folding, the cell cycle, and cytoskeleton regulation. Specifically, genotoxic-stress- and ER stress-related chaperone proteins greatly contributed to the FLJ25439 overexpression phenotypes. The results of this study pave the way to our further understanding of the role of this novel cytokinesis-related protein in protecting cells from environmental stress and tetraploid formation.
a School of Traditional Chinese Medicine; Chang Gung University ; Taoyuan , Taiwan.
Tai-Long
TL
Pan
Shu-Yuan
SY
Hsu
Pei-Wen
PW
Wang
Ya-Ting
YT
Cheng
Yu-Chen
YC
Chang
Sudipta
S
Saha
Jiwei
J
Hu
Pin
P
Ouyang
D000595:Amino Acid Sequence; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018385:Centrosome / Q000378:metabolism*; D043171:Chromosomal Instability; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D048749:Cytokinesis / Q000502:physiology; D059865:Endoplasmic Reticulum Stress; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D018832:Molecular Chaperones / Q000378:metabolism*; D008969:Molecular Sequence Data; D018384:Oxidative Stress / Q000187:drug effects; D017510:Protein Folding; D040901:Proteomics; D016160:Retinoblastoma Protein / Q000378:metabolism; D057891:Tetraploidy; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018832:Molecular Chaperones; D016160:Retinoblastoma Protein; C000604344:TTC23L protein, human; D016159:Tumor Suppressor Protein p53; D006861:Hydrogen Peroxide
2DE PAGE, 2-dimensional polyacrylamide gel electrophoresis; DTT, dithiothreitol; ER stress; ER stress, endoplasmic reticulum stress; FLJ25439; HRP, horseradish peroxidase; IEF, isoelectric focusing; MALDI-TOF MS, matrix-assisted laser desorption ionization-time of flight mass spectrometry; PMF, peptide mass fingerprint; SDS, sodium dodecyl sulfate; anti-apoptosis; chromosomal stability; p53; pRb; protein folding; proteomics; tetraploidy; tumorigenesis