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A novel antiproliferative PKCα-Ras-ERK signaling axis in intestinal epithelial cells
We have previously shown that the serine/threonine kinase PKCα triggers MAPK/ERK kinase (MEK)-dependent G(1)→S cell cycle arrest in intestinal epithelial cells, characterized by downregulation of cyclin D1 and inhibitor of DNA-binding protein 1 (Id1) and upregulation of the cyclin-dependent kinase i...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Biochemistry and Molecular Biology
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9270260/ https://www.ncbi.nlm.nih.gov/pubmed/35697074 http://dx.doi.org/10.1016/j.jbc.2022.102121 |
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author | Kaur, Navneet Lum, Michelle A. Lewis, Robert E. Black, Adrian R. Black, Jennifer D. |
author_facet | Kaur, Navneet Lum, Michelle A. Lewis, Robert E. Black, Adrian R. Black, Jennifer D. |
author_sort | Kaur, Navneet |
collection | PubMed |
description | We have previously shown that the serine/threonine kinase PKCα triggers MAPK/ERK kinase (MEK)-dependent G(1)→S cell cycle arrest in intestinal epithelial cells, characterized by downregulation of cyclin D1 and inhibitor of DNA-binding protein 1 (Id1) and upregulation of the cyclin-dependent kinase inhibitor p21(Cip1). Here, we use pharmacological inhibitors, genetic approaches, siRNA-mediated knockdown, and immunoprecipitation to further characterize antiproliferative ERK signaling in intestinal cells. We show that PKCα signaling intersects the Ras-Raf-MEK-ERK kinase cascade at the level of Ras small GTPases and that antiproliferative effects of PKCα require active Ras, Raf, MEK, and ERK, core ERK pathway components that are also essential for pro-proliferative ERK signaling induced by epidermal growth factor (EGF). However, PKCα-induced antiproliferative signaling differs from EGF signaling in that it is independent of the Ras guanine nucleotide exchange factors (Ras-GEFs), SOS1/2, and involves prolonged rather than transient ERK activation. PKCα forms complexes with A-Raf, B-Raf, and C-Raf that dissociate upon pathway activation, and all three Raf isoforms can mediate PKCα-induced antiproliferative effects. At least two PKCα–ERK pathways that collaborate to promote growth arrest were identified: one pathway requiring the Ras-GEF, RasGRP3, and H-Ras, leads to p21(Cip1) upregulation, while additional pathway(s) mediate PKCα-induced cyclin D1 and Id1 downregulation. PKCα also induces ERK-dependent SOS1 phosphorylation, indicating possible negative crosstalk between antiproliferative and growth-promoting ERK signaling. Importantly, the spatiotemporal activation of PKCα and ERK in the intestinal epithelium in vivo supports the physiological relevance of these pathways and highlights the importance of antiproliferative ERK signaling to tissue homeostasis in the intestine. |
format | Online Article Text |
id | pubmed-9270260 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | American Society for Biochemistry and Molecular Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-92702602022-07-14 A novel antiproliferative PKCα-Ras-ERK signaling axis in intestinal epithelial cells Kaur, Navneet Lum, Michelle A. Lewis, Robert E. Black, Adrian R. Black, Jennifer D. J Biol Chem Research Article We have previously shown that the serine/threonine kinase PKCα triggers MAPK/ERK kinase (MEK)-dependent G(1)→S cell cycle arrest in intestinal epithelial cells, characterized by downregulation of cyclin D1 and inhibitor of DNA-binding protein 1 (Id1) and upregulation of the cyclin-dependent kinase inhibitor p21(Cip1). Here, we use pharmacological inhibitors, genetic approaches, siRNA-mediated knockdown, and immunoprecipitation to further characterize antiproliferative ERK signaling in intestinal cells. We show that PKCα signaling intersects the Ras-Raf-MEK-ERK kinase cascade at the level of Ras small GTPases and that antiproliferative effects of PKCα require active Ras, Raf, MEK, and ERK, core ERK pathway components that are also essential for pro-proliferative ERK signaling induced by epidermal growth factor (EGF). However, PKCα-induced antiproliferative signaling differs from EGF signaling in that it is independent of the Ras guanine nucleotide exchange factors (Ras-GEFs), SOS1/2, and involves prolonged rather than transient ERK activation. PKCα forms complexes with A-Raf, B-Raf, and C-Raf that dissociate upon pathway activation, and all three Raf isoforms can mediate PKCα-induced antiproliferative effects. At least two PKCα–ERK pathways that collaborate to promote growth arrest were identified: one pathway requiring the Ras-GEF, RasGRP3, and H-Ras, leads to p21(Cip1) upregulation, while additional pathway(s) mediate PKCα-induced cyclin D1 and Id1 downregulation. PKCα also induces ERK-dependent SOS1 phosphorylation, indicating possible negative crosstalk between antiproliferative and growth-promoting ERK signaling. Importantly, the spatiotemporal activation of PKCα and ERK in the intestinal epithelium in vivo supports the physiological relevance of these pathways and highlights the importance of antiproliferative ERK signaling to tissue homeostasis in the intestine. American Society for Biochemistry and Molecular Biology 2022-06-10 /pmc/articles/PMC9270260/ /pubmed/35697074 http://dx.doi.org/10.1016/j.jbc.2022.102121 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 Kaur, Navneet Lum, Michelle A. Lewis, Robert E. Black, Adrian R. Black, Jennifer D. A novel antiproliferative PKCα-Ras-ERK signaling axis in intestinal epithelial cells |
title | A novel antiproliferative PKCα-Ras-ERK signaling axis in intestinal epithelial cells |
title_full | A novel antiproliferative PKCα-Ras-ERK signaling axis in intestinal epithelial cells |
title_fullStr | A novel antiproliferative PKCα-Ras-ERK signaling axis in intestinal epithelial cells |
title_full_unstemmed | A novel antiproliferative PKCα-Ras-ERK signaling axis in intestinal epithelial cells |
title_short | A novel antiproliferative PKCα-Ras-ERK signaling axis in intestinal epithelial cells |
title_sort | novel antiproliferative pkcα-ras-erk signaling axis in intestinal epithelial cells |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9270260/ https://www.ncbi.nlm.nih.gov/pubmed/35697074 http://dx.doi.org/10.1016/j.jbc.2022.102121 |
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