Evidence for regulation of mitotic progression through temporal phosphorylation and dephosphorylation of CK2alpha
Authors: D Richard Derksen
David W Litchfield
Nicole A St-Denis
Journal: Molecular and Cellular Biology (2009)
Discipline: MOLECULAR BIOLOGY & GENETICS
Keywords: mitotic progression; protein kinase CK2; phosphorylation; cancer; transformation
Affiliations: Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada., Departments of Biochemistry, Oncology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1

Abstract:  Proper mitotic progression is crucial for maintenance of genomic integrity in proliferating cells and is regulated through an intricate series of events, including protein phosphorylation governed by a complex network of protein kinases. One kinase family implicated in the regulation of mitotic progression is protein kinase CK2, a small family of enzymes that is overexpressed in cancer and induces transformation in mice and cultured fibroblasts. CK2alpha, one isoform of the catalytic subunits of CK2, is maximally phosphorylated at four sites in nocodazole-treated cells. To investigate the effects of CK2alpha phosphorylation on mitotic progression, we generated phosphospecific antibodies against its mitotic phosphorylation sites. In U2OS cells released from S-phase arrest, these antibodies reveal that CK2alpha is most highly phosphorylated in prophase and metaphase. Phosphorylation gradually decreases during anaphase and becomes undetectable during telophase and cytokinesis. Stable expression of phosphomimetic CK2alpha (CK2alpha-4D, CK2alpha-4E) results in aberrant centrosome amplification and chromosomal segregation defects and loss of mitotic cells through mitotic catastrophe. Conversely, cells expressing nonphosphorylatable CK2alpha (CK2alpha-4A) show a decreased ability to arrest in mitosis following nocodazole treatment, suggesting involvement in the spindle assembly checkpoint. Collectively, these studies indicate that reversible phosphorylation of CK2alpha requires precise regulation to allow proper mitotic progression. 

Retracted: No

PubPeer comments:
 Figure 1D. Some panels appear to be visible multiple times. Highlighted with boxes of the same color. ![file] , 
 Thank you for your post. We will examine images from the original experiments and will contact the journal to make appropriate corrections. , 
 Thank you, Dr. Litchfield for your response. Any update to share? I had already reported this concern to the journal in September 2016. Did the journal not contact you back then? This paper was part of a structured search for image duplications in Molecular and Cellular Biology paper, which was published here: https: mcb.asm.org content 38 20 e00309-18.long , 
 2021 correction. https: journals.asm.org doi 10.1128 MCB.00274-21 AUTHOR CORRECTION Volume 29, no. 8, p. 2068u20132081, 2009, https: doi.org 10.1128 MCB.01563-08. Page 2070, Fig. 1D: Due to unintentional error during the preparation of the figure, incorrect images were presented. Correct images, obtained from original data, representing panels 2 to 6 in the top row and panels 5 and 6 in the bottom row are presented below. These corrections do not affect any of the conclusions in the article. We regret the error and apologize for any confusion that may have arisen. ,