Cell Cycle-Dependent Localization of Voltage-Dependent Calcium Channels and the Mitotic Apparatus in a Neuroendocrine Cell Line(AtT-20)

Changes in intracellular calcium are necessary for the successful progression of mitosis in many cells. Both elevation and reduction in intracellular calcium can disrupt mitosis by mechanisms that remain ill defined. In this study we explore the role of transmembrane voltage-gated calcium channels (...

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Main Authors: Karen J. Loechner, Wendy C. Salmon, Jie Fu, Shipra Patel, James T. McLaughlin
Format: Article
Language:English
Published: Wiley 2009-01-01
Series:International Journal of Cell Biology
Online Access:http://dx.doi.org/10.1155/2009/487959
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author Karen J. Loechner
Wendy C. Salmon
Jie Fu
Shipra Patel
James T. McLaughlin
author_facet Karen J. Loechner
Wendy C. Salmon
Jie Fu
Shipra Patel
James T. McLaughlin
author_sort Karen J. Loechner
collection DOAJ
description Changes in intracellular calcium are necessary for the successful progression of mitosis in many cells. Both elevation and reduction in intracellular calcium can disrupt mitosis by mechanisms that remain ill defined. In this study we explore the role of transmembrane voltage-gated calcium channels (CaV channels) as regulators of mitosis in the mouse corticotroph cell line (AtT-20). We report that the nifedipine-sensitive isoform CaV1.2 is localized to the “poleward side” of kinetechores during metaphase and at the midbody during cytokinesis. A second nifedipine-sensitive isoform, CaV1.3, is present at the mid-spindle zone in telophase, but is also seen at the midbody. Nifedipine reduces the rate of cell proliferation, and, utilizing time-lapse microscopy, we show that this is due to a block at the prometaphase stage of the cell cycle. Using Fluo-4 we detect calcium fluxes at sites corresponding to the mid-spindle zone and the midbody region. Another calcium dye, Fura PE3/AM, causes an inhibition of mitosis prior to anaphase that we attribute to a chelation of intracellular calcium. Our results demonstrate a novel, isoform-specific localization of CaV1 channels during cell division and suggest a possible role for these channels in the calcium-dependent events underlying mitotic progression in pituitary corticotrophs.
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spelling doaj-art-b8411b6dd39b4d048071c10cde50eebf2025-08-20T02:19:11ZengWileyInternational Journal of Cell Biology1687-88761687-88842009-01-01200910.1155/2009/487959487959Cell Cycle-Dependent Localization of Voltage-Dependent Calcium Channels and the Mitotic Apparatus in a Neuroendocrine Cell Line(AtT-20)Karen J. Loechner0Wendy C. Salmon1Jie Fu2Shipra Patel3James T. McLaughlin4Division of Pediatric Endocrinology, Department of Pediatrics, University of North Carolina Chapel Hill, Chapel Hill, NC 27599, USAMichael Hooker Microscopy Facility, University of North Carolina Chapel Hill, Chapel Hill, NC 27599, USADepartment of Pharmacology, University of North Carolina Chapel Hill, Chapel Hill, NC 27599, USADivision of Pediatric Endocrinology, Department of Pediatrics, University of North Carolina Chapel Hill, Chapel Hill, NC 27599, USADepartment of Pharmacology, University of North Carolina Chapel Hill, Chapel Hill, NC 27599, USAChanges in intracellular calcium are necessary for the successful progression of mitosis in many cells. Both elevation and reduction in intracellular calcium can disrupt mitosis by mechanisms that remain ill defined. In this study we explore the role of transmembrane voltage-gated calcium channels (CaV channels) as regulators of mitosis in the mouse corticotroph cell line (AtT-20). We report that the nifedipine-sensitive isoform CaV1.2 is localized to the “poleward side” of kinetechores during metaphase and at the midbody during cytokinesis. A second nifedipine-sensitive isoform, CaV1.3, is present at the mid-spindle zone in telophase, but is also seen at the midbody. Nifedipine reduces the rate of cell proliferation, and, utilizing time-lapse microscopy, we show that this is due to a block at the prometaphase stage of the cell cycle. Using Fluo-4 we detect calcium fluxes at sites corresponding to the mid-spindle zone and the midbody region. Another calcium dye, Fura PE3/AM, causes an inhibition of mitosis prior to anaphase that we attribute to a chelation of intracellular calcium. Our results demonstrate a novel, isoform-specific localization of CaV1 channels during cell division and suggest a possible role for these channels in the calcium-dependent events underlying mitotic progression in pituitary corticotrophs.http://dx.doi.org/10.1155/2009/487959
spellingShingle Karen J. Loechner
Wendy C. Salmon
Jie Fu
Shipra Patel
James T. McLaughlin
Cell Cycle-Dependent Localization of Voltage-Dependent Calcium Channels and the Mitotic Apparatus in a Neuroendocrine Cell Line(AtT-20)
International Journal of Cell Biology
title Cell Cycle-Dependent Localization of Voltage-Dependent Calcium Channels and the Mitotic Apparatus in a Neuroendocrine Cell Line(AtT-20)
title_full Cell Cycle-Dependent Localization of Voltage-Dependent Calcium Channels and the Mitotic Apparatus in a Neuroendocrine Cell Line(AtT-20)
title_fullStr Cell Cycle-Dependent Localization of Voltage-Dependent Calcium Channels and the Mitotic Apparatus in a Neuroendocrine Cell Line(AtT-20)
title_full_unstemmed Cell Cycle-Dependent Localization of Voltage-Dependent Calcium Channels and the Mitotic Apparatus in a Neuroendocrine Cell Line(AtT-20)
title_short Cell Cycle-Dependent Localization of Voltage-Dependent Calcium Channels and the Mitotic Apparatus in a Neuroendocrine Cell Line(AtT-20)
title_sort cell cycle dependent localization of voltage dependent calcium channels and the mitotic apparatus in a neuroendocrine cell line att 20
url http://dx.doi.org/10.1155/2009/487959
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