title: Dephosphorylation of CaMKII at T253 controls the metaphase-anaphase transition.
abstract: Calcium/calmodulin-stimulated protein kinase II (CaMKII) is a multi-functional serine/threonine protein kinase that controls a range of cellular functions, including proliferation. The biological properties of CaMKII are regulated by multi-site phosphorylation and targeting via interactions with specific proteins. To investigate the role specific CaMKII phosphorylation sites play in controlling cell proliferation and cell cycle progression, we examined phosphorylation of CaMKII at two sites (T253 and T286) at various stages of the cell cycle, and also examined the effects of overexpression of wild-type (WT), T286D phosphomimic, T253D phosphomimic and T253V phosphonull forms of CaMKIIα in MDA-MB-231 breast cancer and SHSY5Y neuroblastoma cells on cellular proliferation and cell cycle progression. We demonstrate herein that whilst there is no change in total CaMKII expression or T286 phosphorylation throughout the cell cycle, a marked dephosphorylation of CaMKII at T253 occurs during the G2 and/or M phases. Additionally, we show by molecular inhibition, as well as pharmacological activation, that protein phosphatase 2A (PP2A) is the phosphatase responsible for this dephosphorylation. Furthermore, we show that inducible overexpression of WT, T286D and T253V forms of CaMKIIα in MDA-MB-231 and SHSY5Y cells increases cellular proliferation, with no alteration in cell cycle profiles. By contrast, overexpression of a T253D phosphomimic form of CaMKIIα significantly decreases proliferation, and cells accumulate in mitosis, specifically in metaphase. Taken together, these results strongly suggest that the dephosphorylation of CaMKII at T253 is involved in controlling the cell cycle, specifically the metaphase-anaphase transition.
authors.affiliation: School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia; The Hunter Medical Research Institute, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Hoffman
authors.affiliation: School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia; The Hunter Medical Research Institute, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Helen
authors.initials: H
authors.lastname: Carpenter
authors.affiliation: School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia; The Hunter Medical Research Institute, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Kahl
authors.affiliation: School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia; The Hunter Medical Research Institute, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Lauren F
authors.initials: LF
authors.lastname: Watt
authors.affiliation: School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia; The Hunter Medical Research Institute, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Phillip W
authors.initials: PW
authors.lastname: Dickson
authors.affiliation: School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia; The Hunter Medical Research Institute, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: John A P
authors.initials: JA
authors.lastname: Rostas
authors.affiliation: School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia; The Hunter Medical Research Institute, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Verrills
authors.affiliation: School of Biomedical Sciences and Pharmacy, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia; The Hunter Medical Research Institute, Faculty of Health, The University of Newcastle, Callaghan, New South Wales, Australia. Electronic address: Kathryn.Skelding@newcastle.edu.au.
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Skelding
mesh_terms: D019943:Amino Acid Substitution; D000705:Anaphase; D017209:Apoptosis; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D008677:Metaphase; D008938:Mitosis; D010766:Phosphorylation; D054648:Protein Phosphatase 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism
chemical_list: D034741:RNA, Small Interfering; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D054648:Protein Phosphatase 2
keywords: CaMKII; Calcium/calmodulin stimulated protein kinase II; Cell cycle; Metaphase; Protein phosphatase 2A; Protein phosphorylation