Signaling of MK2 sustains robust AP1 activity for triple negative breast cancer tumorigenesis through direct phosphorylation of JAB1
Abstract Triple negative breast cancer (TNBC) cells are generally more invasive than estrogen receptor-positive (ER + ) breast cancer cells. Consistent with the importance of activator protein 1 (AP1) transcription factors in invasion, AP1 activity is much higher in TNBC lines than ER + lines. In TN...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2021-07-01
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| Series: | npj Breast Cancer |
| Online Access: | https://doi.org/10.1038/s41523-021-00300-1 |
| _version_ | 1797428236704022528 |
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| author | Haoming Chen Ravi Padia Tao Li Yue Li Bin Li Lingtao Jin Shuang Huang |
| author_facet | Haoming Chen Ravi Padia Tao Li Yue Li Bin Li Lingtao Jin Shuang Huang |
| author_sort | Haoming Chen |
| collection | DOAJ |
| description | Abstract Triple negative breast cancer (TNBC) cells are generally more invasive than estrogen receptor-positive (ER + ) breast cancer cells. Consistent with the importance of activator protein 1 (AP1) transcription factors in invasion, AP1 activity is much higher in TNBC lines than ER + lines. In TNBC cells, robust AP1 activity is facilitated by both ERK and p38MAPK signaling pathways. While ERK signaling pathway regulates AP1 activity by controlling the abundance of AP1 transcription factors, p38MAPK signaling pathway does it by enhancing AP1 binding to AP1 sites without altering their abundance. Here, we show that p38MAPK regulation of AP1 activity involves both MAPKAPK2 (MK2) and JAB1, a known JUN-binding protein. MK2 not only interacts with JAB1 but also directly phosphorylates JAB1 at Ser177 in TNBC cells. Interestingly, Ser177 phosphorylation does not affect JAB1 and JUN interaction. Instead, interfering with p38MAPK signaling pathway or introducing an S to A point mutation at Ser177 of JAB1 reduces JUN recruitment to the AP1 sites in cyclin D1, urokinase plasminogen activator (uPA) and uPA receptor promoters. Moreover, knockdown of JAB1 diminishes >60% of AP1 transcriptional activity in TNBC cells. Taken together, these results indicate that MK2-mediated phosphorylation of JAB1 facilitates JUN recruitment to AP1 sites, thus augmenting AP1 activity. In line with the role of JAB1 in AP1 activity, silencing JAB1 leads to dramatic reduction in TNBC cell growth, in vitro invasion and in vivo tumor outgrowth. This study suggests that the p38MAPK-MK2 signaling pathway promotes TNBC tumorigenesis by sustaining robust AP1 activity. |
| first_indexed | 2024-03-09T08:56:11Z |
| format | Article |
| id | doaj.art-6809040fae854e9e929618df09a0fab9 |
| institution | Directory Open Access Journal |
| issn | 2374-4677 |
| language | English |
| last_indexed | 2024-03-09T08:56:11Z |
| publishDate | 2021-07-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj Breast Cancer |
| spelling | doaj.art-6809040fae854e9e929618df09a0fab92023-12-02T13:07:59ZengNature Portfolionpj Breast Cancer2374-46772021-07-017111310.1038/s41523-021-00300-1Signaling of MK2 sustains robust AP1 activity for triple negative breast cancer tumorigenesis through direct phosphorylation of JAB1Haoming Chen0Ravi Padia1Tao Li2Yue Li3Bin Li4Lingtao Jin5Shuang Huang6The Ministry of Education Key Laboratory of Contemporary Anthropology, College of Life Science, Fudan UniversityDepartment of Anatomy and Cell Biology, University of Florida College of MedicineDepartment of Anatomy and Cell Biology, University of Florida College of MedicineDepartment of Anatomy and Cell Biology, University of Florida College of MedicineDepartment of Anatomy and Cell Biology, University of Florida College of MedicineDepartment of Anatomy and Cell Biology, University of Florida College of MedicineDepartment of Anatomy and Cell Biology, University of Florida College of MedicineAbstract Triple negative breast cancer (TNBC) cells are generally more invasive than estrogen receptor-positive (ER + ) breast cancer cells. Consistent with the importance of activator protein 1 (AP1) transcription factors in invasion, AP1 activity is much higher in TNBC lines than ER + lines. In TNBC cells, robust AP1 activity is facilitated by both ERK and p38MAPK signaling pathways. While ERK signaling pathway regulates AP1 activity by controlling the abundance of AP1 transcription factors, p38MAPK signaling pathway does it by enhancing AP1 binding to AP1 sites without altering their abundance. Here, we show that p38MAPK regulation of AP1 activity involves both MAPKAPK2 (MK2) and JAB1, a known JUN-binding protein. MK2 not only interacts with JAB1 but also directly phosphorylates JAB1 at Ser177 in TNBC cells. Interestingly, Ser177 phosphorylation does not affect JAB1 and JUN interaction. Instead, interfering with p38MAPK signaling pathway or introducing an S to A point mutation at Ser177 of JAB1 reduces JUN recruitment to the AP1 sites in cyclin D1, urokinase plasminogen activator (uPA) and uPA receptor promoters. Moreover, knockdown of JAB1 diminishes >60% of AP1 transcriptional activity in TNBC cells. Taken together, these results indicate that MK2-mediated phosphorylation of JAB1 facilitates JUN recruitment to AP1 sites, thus augmenting AP1 activity. In line with the role of JAB1 in AP1 activity, silencing JAB1 leads to dramatic reduction in TNBC cell growth, in vitro invasion and in vivo tumor outgrowth. This study suggests that the p38MAPK-MK2 signaling pathway promotes TNBC tumorigenesis by sustaining robust AP1 activity.https://doi.org/10.1038/s41523-021-00300-1 |
| spellingShingle | Haoming Chen Ravi Padia Tao Li Yue Li Bin Li Lingtao Jin Shuang Huang Signaling of MK2 sustains robust AP1 activity for triple negative breast cancer tumorigenesis through direct phosphorylation of JAB1 npj Breast Cancer |
| title | Signaling of MK2 sustains robust AP1 activity for triple negative breast cancer tumorigenesis through direct phosphorylation of JAB1 |
| title_full | Signaling of MK2 sustains robust AP1 activity for triple negative breast cancer tumorigenesis through direct phosphorylation of JAB1 |
| title_fullStr | Signaling of MK2 sustains robust AP1 activity for triple negative breast cancer tumorigenesis through direct phosphorylation of JAB1 |
| title_full_unstemmed | Signaling of MK2 sustains robust AP1 activity for triple negative breast cancer tumorigenesis through direct phosphorylation of JAB1 |
| title_short | Signaling of MK2 sustains robust AP1 activity for triple negative breast cancer tumorigenesis through direct phosphorylation of JAB1 |
| title_sort | signaling of mk2 sustains robust ap1 activity for triple negative breast cancer tumorigenesis through direct phosphorylation of jab1 |
| url | https://doi.org/10.1038/s41523-021-00300-1 |
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