Browsing by Subject "MTOR"

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    IKBKE inhibits TSC1 to activate the mTOR/S6K pathway for oncogenic transformation
    (TUBITAK, 2018) Göktuna, Serkan İsmail
    IKBKE (IKKε) has emerged as a key modulator of multiple substrates, controlling oncogenic pathways in various malignancies. mTOR signaling, required for cellular growth, proliferation, and vascular angiogenesis in cancer, is potentially one of the pathways regulated by IKKε. Upon activation by various stimuli, PI3K/AKT or similar effectors can relieve the inhibitory effect of the TSC1/TSC2 complex through their phosphorylation to favor mTOR/S6K activation in the downstream. Therefore, any activity that interferes with PI3K/AKT or their downstream targets, such as TSC1/2 or GSK3α/β, may activate the mTOR/S6K pathway for oncogenic transformation in normal cells. Previous studies have shown that PI3K/AKT can be directly phosphoregulated by IKKε. Here, we propose a new regulatory function for IKKε in the mTOR/S6K pathway through its direct interaction with TSC1, leading to TSC1 phosphorylation, which is vital to suppress its inhibitory role in mTOR activation. Experimentally, upon IKKε deficiency in colorectal cancer cells, we observed that S6K activity was diminished while TSC1 levels were found to be stabilized. We hypothesized that these observations may result from direct interaction between IKKε and TSC1. Indeed, the interaction of these two proteins involves the phosphoregulation of TSC1 in various cell lines. Therefore, we propose a mechanism where IKKε, through regulating TSC1 stability in cancer cells, may create an alternative regulatory loop for the activation of mTOR signaling. These results can potentially be important for the development of novel therapeutic strategies targeting mTOR signaling.
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    Mammalian target of rapamycin (mTOR), aging, neuroscience, and their association with aging-related diseases
    (Elsevier Inc., 2016) Celebi-Birand, Ergül Dilan; Karoğlu, Elif Tuğçe; Doldur-Ballı, Füsun; Adams, Michelle M.; Maiese, K.
    Normal aging is accompanied by cognitive impairment with subtle cellular and molecular changes in the brain, whereas, pathological brain aging manifests as severe behavioral impairments with cellular pathology. Understanding the factors that contribute to both states is undoubtedly important for determining appropriate interventions that alter their progression. Mammalian target of rapamycin (mTOR) signaling has been implicated in affecting lifespan and age-related diseases such as cancer. The relationship of mTOR signaling with pathological brain aging has been more extensively studied, whereas the association with normal brain aging is not well understood. In this chapter we present information about normal and pathological brain aging, the relationship with mTOR signaling and use information from other age-related diseases to suggest that mTOR may have a role in promoting the cellular and molecular changes that underlie age-related cognitive changes. Future work should be directed towards understanding the precise role of mTOR signaling in brain aging. © 2016 Elsevier Inc. All rights reserved.