期刊
FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY
卷 9, 期 -, 页码 -出版社
FRONTIERS MEDIA SA
DOI: 10.3389/fcell.2021.709398
关键词
autophagy; PI3K I; T cells; lipid kinase; lipid phosphatase; cytokines; HIV
资金
- NIH [AI074944, AI125552]
Autophagy, an important mechanism regulating T lymphocyte homeostasis, is induced by starvation and T cell receptor activation requiring PI(3)P production, while common gamma chain cytokines suppress autophagy despite activating the PI3K pathway. Lack of PI3KI subunits p85 and p55 impedes TCR-mediated autophagy, indicating their crucial role in linking TCR activation to autophagy.
Autophagy, a highly conserved intracellular process, has been identified as a novel mechanism regulating T lymphocyte homeostasis. Herein, we demonstrate that both starvation- and T cell receptor-mediated autophagy induction requires class I phosphatidylinositol-3 kinases to produce PI(3)P. In contrast, common gamma chain cytokines are suppressors of autophagy despite their ability to activate the PI3K pathway. T cells lacking the PI3KI regulatory subunits, p85 and p55, were almost completely unable to activate TCR-mediated autophagy and had concurrent defects in PI(3)P production. Additionally, T lymphocytes upregulate polyinositol phosphatases in response to autophagic stimuli, and the activity of the inositol phosphatases Inpp4 and SHIP are required for TCR-mediated autophagy induction. Addition of exogenous PI(3,4)P-2 can supplement cellular PI(3)P and accelerate the outcome of activation-induced autophagy. TCR-mediated autophagy also requires internalization of the TCR complex, suggesting that this kinase/phosphatase activity is localized in internalized vesicles. Finally, HIV-induced bystander CD4(+) T cell autophagy is dependent upon PI3KI. Overall, our data elucidate an important pathway linking TCR activation to autophagy, via induction of PI3KI activity and inositol phosphatase upregulation to produce PI(3)P.
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