Phosphorylation-Dependent Intra-Domain Interaction of the Cx37 Carboxyl-Terminus Controls Cell Survival

Differential phosphorylation of the carboxyl-terminus of connexin 37 (Cx37-CT) regulates phenotypic switching between cell growth phenotypes (cell death, cell cycle arrest, proliferation). The specific phosphorylation events in the Cx37-CT that are necessary for these growth regulatory effects are c...

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Main Authors: Nicole L. Jacobsen, Tasha K. Pontifex, Paul R. Langlais, Janis M. Burt
Format: Article
Language:English
Published: MDPI AG 2019-02-01
Series:Cancers
Subjects:
Online Access:https://www.mdpi.com/2072-6694/11/2/188
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spelling doaj-a23419b3146249b98939a0904325ed5c2020-11-25T01:33:49ZengMDPI AGCancers2072-66942019-02-0111218810.3390/cancers11020188cancers11020188Phosphorylation-Dependent Intra-Domain Interaction of the Cx37 Carboxyl-Terminus Controls Cell SurvivalNicole L. Jacobsen0Tasha K. Pontifex1Paul R. Langlais2Janis M. Burt3Department of Physiology, University of Arizona, Tucson, AZ 85724, USADepartment of Physiology, University of Arizona, Tucson, AZ 85724, USADepartment of Medicine, University of Arizona, Tucson, AZ 85724, USADepartment of Physiology, University of Arizona, Tucson, AZ 85724, USADifferential phosphorylation of the carboxyl-terminus of connexin 37 (Cx37-CT) regulates phenotypic switching between cell growth phenotypes (cell death, cell cycle arrest, proliferation). The specific phosphorylation events in the Cx37-CT that are necessary for these growth regulatory effects are currently unknown. Through the combined use of deletion and site specific (de)phospho-mimetic Cx37-CT mutants, our data suggest a phosphorylation-dependent interaction between the mid-tail (aa 273⁻317) and end-tail (aa 318⁻333) portions of the Cx37-CT that regulates cell survival. As detected by mass spectrometry, Cx37 was phosphorylated at serines 275, 321, and 328; phosphomimetic mutations of these sites resulted in cell death when expressed in rat insulinoma cells. Alanine substitution at S328, but not at S275 or S321, also triggered cell death. Cx37-S275D uniquely induced the death of only low density, non-contact forming cells, but neither hemichannel open probability nor channel conductance distinguished death-inducing mutants. As channel function is necessary for cell death, together the data suggest that the phosphorylation state of the Cx37-CT controls an intra-domain interaction within the CT that modifies channel function and induces cell death.https://www.mdpi.com/2072-6694/11/2/188gap junctionconnexincell cyclecell deathgatingphosphorylation
collection DOAJ
language English
format Article
sources DOAJ
author Nicole L. Jacobsen
Tasha K. Pontifex
Paul R. Langlais
Janis M. Burt
spellingShingle Nicole L. Jacobsen
Tasha K. Pontifex
Paul R. Langlais
Janis M. Burt
Phosphorylation-Dependent Intra-Domain Interaction of the Cx37 Carboxyl-Terminus Controls Cell Survival
Cancers
gap junction
connexin
cell cycle
cell death
gating
phosphorylation
author_facet Nicole L. Jacobsen
Tasha K. Pontifex
Paul R. Langlais
Janis M. Burt
author_sort Nicole L. Jacobsen
title Phosphorylation-Dependent Intra-Domain Interaction of the Cx37 Carboxyl-Terminus Controls Cell Survival
title_short Phosphorylation-Dependent Intra-Domain Interaction of the Cx37 Carboxyl-Terminus Controls Cell Survival
title_full Phosphorylation-Dependent Intra-Domain Interaction of the Cx37 Carboxyl-Terminus Controls Cell Survival
title_fullStr Phosphorylation-Dependent Intra-Domain Interaction of the Cx37 Carboxyl-Terminus Controls Cell Survival
title_full_unstemmed Phosphorylation-Dependent Intra-Domain Interaction of the Cx37 Carboxyl-Terminus Controls Cell Survival
title_sort phosphorylation-dependent intra-domain interaction of the cx37 carboxyl-terminus controls cell survival
publisher MDPI AG
series Cancers
issn 2072-6694
publishDate 2019-02-01
description Differential phosphorylation of the carboxyl-terminus of connexin 37 (Cx37-CT) regulates phenotypic switching between cell growth phenotypes (cell death, cell cycle arrest, proliferation). The specific phosphorylation events in the Cx37-CT that are necessary for these growth regulatory effects are currently unknown. Through the combined use of deletion and site specific (de)phospho-mimetic Cx37-CT mutants, our data suggest a phosphorylation-dependent interaction between the mid-tail (aa 273⁻317) and end-tail (aa 318⁻333) portions of the Cx37-CT that regulates cell survival. As detected by mass spectrometry, Cx37 was phosphorylated at serines 275, 321, and 328; phosphomimetic mutations of these sites resulted in cell death when expressed in rat insulinoma cells. Alanine substitution at S328, but not at S275 or S321, also triggered cell death. Cx37-S275D uniquely induced the death of only low density, non-contact forming cells, but neither hemichannel open probability nor channel conductance distinguished death-inducing mutants. As channel function is necessary for cell death, together the data suggest that the phosphorylation state of the Cx37-CT controls an intra-domain interaction within the CT that modifies channel function and induces cell death.
topic gap junction
connexin
cell cycle
cell death
gating
phosphorylation
url https://www.mdpi.com/2072-6694/11/2/188
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