| Autor: |
Jennifer Ly Tsang, Song Hui Jia, Jean Parodo, Pamela Plant, Monika Lodyga, Emmanuel Charbonney, Katalin Szaszi, Andras Kapus, John C Marshall |
| Jazyk: |
angličtina |
| Rok vydání: |
2016 |
| Předmět: |
|
| Zdroj: |
PLoS ONE, Vol 11, Iss 4, p e0153946 (2016) |
| Druh dokumentu: |
article |
| ISSN: |
1932-6203 |
| DOI: |
10.1371/journal.pone.0153946 |
| Popis: |
Src family tyrosine kinases (SFKs) phosphorylate caspase-8A at tyrosine (Y) 397 resulting in suppression of apoptosis. In addition, the phosphorylation of caspase-8A at other sites including Y465 has been implicated in the regulation of caspase-8 activity. However, the functional consequences of these modifications on caspase-8 processing/activity have not been elucidated. Moreover, various Src substrates are known to act as potent Src regulators, but no such role has been explored for caspase-8. We asked whether the newly identified caspase-8 phosphorylation sites might regulate caspase-8 activation and conversely, whether caspase-8 phosphorylation might affect Src activity. Here we show that Src phosphorylates caspase-8A at multiple tyrosine sites; of these, we have focused on Y397 within the linker region and Y465 within the p12 subunit of caspase-8A. We show that phosphomimetic mutation of caspase-8A at Y465 prevents its cleavage and the subsequent activation of caspase-3 and suppresses apoptosis. Furthermore, simultaneous phosphomimetic mutation of caspase-8A at Y397 and Y465 promotes the phosphorylation of c-Src at Y416 and increases c-Src activity. Finally, we demonstrate that caspase-8 activity prevents its own tyrosine phosphorylation by Src. Together these data reveal that dual phosphorylation converts caspase-8 from a pro-apoptotic to a pro-survival mediator. Specifically, tyrosine phosphorylation by Src renders caspase-8 uncleavable and thereby inactive, and at the same time converts it to a Src activator. This novel dynamic interplay between Src and caspase-8 likely acts as a potent signal-integrating switch directing the cell towards apoptosis or survival. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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