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Bcl-xL deamidation is regulated by multiple ion transporters and is intramolecularly catalyzed.

Authors
  • Dho, So Hee1
  • Manson, Scott R2
  • Jung, Sung Hee3
  • Lim, Jae Cheong3
  • Weintraub, Steven J4
  • 1 Radioisotope Research Division, Department of Research Reactor Utilization, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea; Division of Urology and The Alvin J. Siteman Cancer Center, Washington University School of Medicine, Saint Louis, MO 63110, United States. Electronic address: [email protected] , (North Korea)
  • 2 Division of Urology and The Alvin J. Siteman Cancer Center, Washington University School of Medicine, Saint Louis, MO 63110, United States. , (United States)
  • 3 Radioisotope Research Division, Department of Research Reactor Utilization, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea. , (North Korea)
  • 4 Division of Urology and The Alvin J. Siteman Cancer Center, Washington University School of Medicine, Saint Louis, MO 63110, United States; Department of Internal Medicine, St. Louis VA Medical Center-John Cochran Division, 915 North Grand Blvd, Saint Louis, MO 63106, United States; Department of Internal Medicine, Washington University School of Medicine, Saint Louis, MO 63110, United States. Electronic address: [email protected] , (United States)
Type
Published Article
Journal
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research
Publisher
Elsevier
Publication Date
Jul 01, 2018
Volume
1865
Issue
7
Pages
995–1001
Identifiers
DOI: 10.1016/j.bbamcr.2018.04.009
PMID: 29694915
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

In susceptible tumor cells, DNA-damaging antineoplastic agents induce an increase in intracellular pH during the premitochondrial stage of apoptosis. The rate of nonenzymatic deamidation of two asparagines in the anti-apoptotic protein Bcl-xL is accelerated by this increase in pH. Deamidation of these asparagines is a signal for the degradation of Bcl-xL, which is a component of the apoptotic response to DNA damage. It has previously been shown that the increase in pH is mediated by the ion transporter Na+/H+ exchanger 1 in some cells. Here we demonstrate that one or more additional ion transporters also have a role in the regulation of Bcl-xL deamidation in at least some tumor cell lines and fibroblasts. As a second, independent finding, we report that there are histidines in close proximity to the Bcl-xL deamidation sites that are highly conserved in land-dwelling species and we present evidence that deamidation of human Bcl-xL is intramolecularly catalyzed in a manner that is dependent upon these histidines. Further, we present evidence that these histidines act as a pH-sensitive switch that enhances the effect of the increase in pH on the rate of Bcl-xL deamidation. The conservation of such histidines implies that human Bcl-xL is in essence "designed" to be deamidated, which provides further evidence that deamidation serves as a bona fide regulatory post-translational modification of Bcl-xL. Copyright © 2018 Elsevier B.V. All rights reserved.

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