ERK1 and ERK2 share a great deal of homology and have been presumed to have similar functions. Available antibodies recognize both isoforms making the elucidation of functional differences challenging. Mitogen-activated protein (MAP) kinase networks are commonly depicted in the literature as linear and sequential phosphorylation cascades; however, the activation of these pathways is not mutually exclusive. Little doubt exists that MAP kinases engage in crosstalk, but the extent or the direct effect of these “conversations” is unclear. Here, we report the possible points of direct interaction as “crosstalk” points between ERK1 and JNK1 and a potential mechanism for ERK1 function in repressing Ras/JNK-mediated cell transformation. ERK1, but not ERK2, directly interacts with and antagonizes JNK1 phosphorylation and activity, resulting in suppression of neoplastic cell transformation mediated by the Ras/JNK/c-Jun signaling pathway. Interestingly, ERK1 phosphorylation was increased in normal tissues compared to liver cancer tissues. Furthermore, predominant JNK/c-Jun activation was observed in liver cancer tissues. These phenomena can provide evidence for the existence of a functional association between ERK and JNK signaling pathways during in vivo tumorigenesis. Overall, our findings provide new evidence supporting the paradigm of an ERK1/JNK1 antagonistic interaction as a novel mechanism of trans-regulation between different MAP kinase signaling modules. J. Cell. Biochem. 118: 2357–2370, 2017.
|Original language||English (US)|
|Number of pages||14|
|Journal||Journal of Cellular Biochemistry|
|State||Published - Aug 1 2017|
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Ministry of Education, Science and Technology (NRF-2009-0073802) and by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI15C0001).
© 2017 Wiley Periodicals, Inc.
- CELL TRANSFORMATION
- PROTEIN INTERACTION