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β-Cells retain a pool of insulin-containing secretory vesicles regulated by adherens junctions and the cadherin-binding protein p120 catenin
The β-cells of the islets of Langerhans are the sole producers of insulin in the human body. In response to rising glucose levels, insulin-containing vesicles inside β-cells fuse with the plasma membrane and release their cargo. However, the mechanisms regulating this process are only partly underst...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Biochemistry and Molecular Biology
2022
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9358467/ https://www.ncbi.nlm.nih.gov/pubmed/35809641 http://dx.doi.org/10.1016/j.jbc.2022.102240 |
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author | Dissanayake, Waruni C. Shepherd, Peter R. |
author_facet | Dissanayake, Waruni C. Shepherd, Peter R. |
author_sort | Dissanayake, Waruni C. |
collection | PubMed |
description | The β-cells of the islets of Langerhans are the sole producers of insulin in the human body. In response to rising glucose levels, insulin-containing vesicles inside β-cells fuse with the plasma membrane and release their cargo. However, the mechanisms regulating this process are only partly understood. Previous evidence indicated reductions in α-catenin elevate insulin release, while reductions in β-catenin decrease insulin release. α- and β-catenin contribute to cellular regulation in a range of ways but one is as members of the adherens junction complex. Therefore, we investigated the effects of adherens junctions on insulin release. We show in INS-1E β-cells knockdown of either E- or N-cadherin had only small effects on insulin secretion, but simultaneous knockdown of both cadherins resulted in a significant increase in basal insulin release to the same level as glucose-stimulated release. This double knockdown also significantly attenuated levels of p120 catenin, a cadherin-binding partner involved in regulating cadherin turnover. Conversely, reducing p120 catenin levels with siRNA destabilized both E- and N-cadherin, and this was also associated with an increase in levels of insulin secreted from INS-1E cells. Furthermore, there were also changes in these cells consistent with higher insulin release, namely reductions in levels of F-actin and increased intracellular free Ca(2+) levels in response to KCl-induced membrane depolarization. Taken together, these data provide evidence that adherens junctions play important roles in retaining a pool of insulin secretory vesicles within the cell and establish a role for p120 catenin in regulating this process. |
format | Online Article Text |
id | pubmed-9358467 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | American Society for Biochemistry and Molecular Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-93584672022-08-09 β-Cells retain a pool of insulin-containing secretory vesicles regulated by adherens junctions and the cadherin-binding protein p120 catenin Dissanayake, Waruni C. Shepherd, Peter R. J Biol Chem Research Article The β-cells of the islets of Langerhans are the sole producers of insulin in the human body. In response to rising glucose levels, insulin-containing vesicles inside β-cells fuse with the plasma membrane and release their cargo. However, the mechanisms regulating this process are only partly understood. Previous evidence indicated reductions in α-catenin elevate insulin release, while reductions in β-catenin decrease insulin release. α- and β-catenin contribute to cellular regulation in a range of ways but one is as members of the adherens junction complex. Therefore, we investigated the effects of adherens junctions on insulin release. We show in INS-1E β-cells knockdown of either E- or N-cadherin had only small effects on insulin secretion, but simultaneous knockdown of both cadherins resulted in a significant increase in basal insulin release to the same level as glucose-stimulated release. This double knockdown also significantly attenuated levels of p120 catenin, a cadherin-binding partner involved in regulating cadherin turnover. Conversely, reducing p120 catenin levels with siRNA destabilized both E- and N-cadherin, and this was also associated with an increase in levels of insulin secreted from INS-1E cells. Furthermore, there were also changes in these cells consistent with higher insulin release, namely reductions in levels of F-actin and increased intracellular free Ca(2+) levels in response to KCl-induced membrane depolarization. Taken together, these data provide evidence that adherens junctions play important roles in retaining a pool of insulin secretory vesicles within the cell and establish a role for p120 catenin in regulating this process. American Society for Biochemistry and Molecular Biology 2022-07-06 /pmc/articles/PMC9358467/ /pubmed/35809641 http://dx.doi.org/10.1016/j.jbc.2022.102240 Text en © 2022 The Authors https://creativecommons.org/licenses/by-nc-nd/4.0/This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). |
spellingShingle | Research Article Dissanayake, Waruni C. Shepherd, Peter R. β-Cells retain a pool of insulin-containing secretory vesicles regulated by adherens junctions and the cadherin-binding protein p120 catenin |
title | β-Cells retain a pool of insulin-containing secretory vesicles regulated by adherens junctions and the cadherin-binding protein p120 catenin |
title_full | β-Cells retain a pool of insulin-containing secretory vesicles regulated by adherens junctions and the cadherin-binding protein p120 catenin |
title_fullStr | β-Cells retain a pool of insulin-containing secretory vesicles regulated by adherens junctions and the cadherin-binding protein p120 catenin |
title_full_unstemmed | β-Cells retain a pool of insulin-containing secretory vesicles regulated by adherens junctions and the cadherin-binding protein p120 catenin |
title_short | β-Cells retain a pool of insulin-containing secretory vesicles regulated by adherens junctions and the cadherin-binding protein p120 catenin |
title_sort | β-cells retain a pool of insulin-containing secretory vesicles regulated by adherens junctions and the cadherin-binding protein p120 catenin |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9358467/ https://www.ncbi.nlm.nih.gov/pubmed/35809641 http://dx.doi.org/10.1016/j.jbc.2022.102240 |
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