Distinct Classes of Phosphatidylinositol 3′-Kinases Are Involved in Signaling Pathways That Control Macroautophagy in HT-29 Cells*

By A. Petiot, E. Ogier-Denis, E. Blommaart, A. Meijer, P. Codogno. Journal of Biological Chemistry, 2000

1,263 citations recorded by the source corpus.

3-Methyladenine which stops macroautophagy at the sequestration step in mammalian cells also inhibits the phosphoinositide 3-kinase (PI3K) activity raising the possibility that PI3K signaling controls the macroautophagic pathway (Blommaart, E. F. C., Krause, U., Schellens, J. P. M., Vreeling-Sindelárová, H., and Meijer, A. J. (1997)Eur. J. Biochem. 243, 240–246). The aim of this study was to identify PI3Ks involved in the control of macroautophagic sequestration in human colon cancer HT-29 cells. An increase of class I PI3K products (phosphatidylinositol 3,4-bisphosphate and phosphatidylinositol 3,4,5-triphosphate) caused by either feeding cells with synthetic lipids (dipalmitoyl phosphatidylinositol 3,4-bisphosphate and dipalmitoyl phosphatidylinositol 3,4,5-triphosphate) or by stimulating the enzymatic activity by interleukin-13 reduced macroautophagy. In contrast, an increase in the class III PI3K product (phosphatidylinositol 3-phosphate), either by feeding cells with a synthetic lipid or by overexpressing the p150 adaptor, stimulates macroautophagy. Transfection of a specific class III PI3K antisense oligonucleotide greatly inhibited the rate of macroautophagy. In accordance with a role of class III PI3K, wortmannin (an inhibitor of PI3Ks) inhibits macroautophagic sequestration and protein degradation in the low nanomolar range (IC50 5–15 nm). Further in vitro enzymatic assay showed that 3-methyladenine inhibits the class III PI3K activity. Dipalmitoyl phosphatidylinositol 3-phosphate supplementation or p150 overexpression rescued the macroautophagic pathway in HT-29 cells overexpressing a GTPase-deficient mutant of the Gαi3 protein suggesting that both class III PI3K and trimeric Gi3 protein signaling are required in the control macroautophagy in HT-29 cells. In conclusion, our results demonstrate that distinct classes of PI3K control the macroautophagic pathway in opposite directions. The roles of PI3Ks in macroautophagy are discussed in the context of membrane recycling.

Subfields: Cell Biology, Epidemiology

View Paper: https://www.semanticscholar.org/paper/6b5e978b6ee2b44ed9651d1a391eff867f9582b4

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Citations in the corpus

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (2012, positive): “class I phosphoinositide 3-kinases (PI3Ks) as well as class III PtdIns3Ks.(132,330,1145) The class I enzymes generate products such as PtdIns(3,4,5)P3 that inhibit autophagic sequestration, whereas the class III product (PtdIns3P) generally stimulates”
The autophagosomal–lysosomal compartment in programmed cell death (2001, background): “However, recent studies on human cancer cells revealed that distinct classes of phosphatidylinositol-3-kinases act in opposite directions in the pathways signalling for sequestration.(54) Thus, the class III PI3-K product PtdIns(3)P is required for sequestration; formation of PtdIns(3)P as well as o”
Autophagy and signaling: their role in cell survival and cell death (2005, background): “3-Methyladenine (3-MA), the specific inhibitor of autophagy, turned out to be an inhibitor of PI3K, which explains why it has an inhibitory effect on both autophagy and S6 phosphorylation.(26,27) Class-III PI3K (and its adaptor p150) was also found to be necessary for autophagy in yeast.”
Two Beclin 1-binding proteins, Atg14L and Rubicon, reciprocally regulate autophagy at different stages (2009, neutral): “dtd" [ ]> Macroautophagy, hereafter referred to as autophagy, is an intracellular process in which cytoplasmic materials are transported by autophagosomes to lysosomes for degradatio”
Growth factor regulation of autophagy and cell survival in the absence of apoptosis. (2005, methodology): “…therefore we used two independent and widely used inhibitors of macroautophagy, 3-methylad- grown in the absence of IL-3 were smaller, displayed LC3-positive autophagosomes in their cytoplasm, andenine (3-MA) and chloroquine (CQ) (Mizushima et al., 2002; Petiot et al., 2000) to block autophagy.”
Autophagy, Immunity, and Microbial Adaptations (2009, background): “At yet another level, highly virulent strains of M. tuberculosis elicit more IL-4 and IL-13 (Manca et al., 2004), the Th2 cytokines known to inhibit autophagy (Petiot et al., 2000), and suppress aspects of APMA (Harris et al., 2007).”
Eaten alive: a history of macroautophagy (2010, background): “Indeed, Codogno's group, in collaboration with Meijer's laboratory, showed that the class III PtdIns3K product, phosphatidylinositol 3-phosphate (PtdIns(3)P), is essential for autophagy, whereas the class I PtdIns3K products, phosphatidylinositol (3,4)-bisphosphate (PtdIns(3,4)P 2 ) and phosphatidyl”
Growth arrest and autophagy are required for salivary gland cell degradation in Drosophila. (2007, positive): “In multicellular organisms, autophagy is negatively regulated by class I PI3K signaling via TOR ( Petiot et al., 2000; Scott et al., 2004).”
Rab7 is required for the normal progression of the autophagic pathway in mammalian cells (2004, background): “Wortmannin (WM) is a potent PI 3-kinase inhibitor that blocks the formation of autophagic vacuoles (Petiot et al., 2000; Munafo and Colombo, 2001).”
The role of autophagy in cancer development and response to therapy (2005, background): “By contrast, class III PI3K promotes the sequestration of cytoplasmic material that occurs during autophag”
PI(5)P Regulates Autophagosome Biogenesis (2015, background): “In the same way that PI(3)P alone is sufficient to stimulate autophagy in mammalian cells (Petiot et al., 2000), we found that addition of exogenous PI(5)P di-C16 significantly increased LC3-II levels and LC3-positive autophagic vesicle numbers (Figures 1A–1D).”
Dynamics and diversity in autophagy mechanisms: lessons from yeast (2009, background): “The activity of PtdIns 3-kinase is essential for autophag”
Guidelines for the use and interpretation of assays for monitoring autophagy (2012, background): “Sequestration inhibitors, including 3-MA, LY294002 and wortmannin, inhibit class I as well as class III PtdIns3Ks.134,257,707 The class I enzymes generate products [PtdIns(3,4,5)P3] that inhibit autophagic sequestration, whereas the class III product (PtdIns3P) generally stimulates autophagic seques”
Beclin–phosphatidylinositol 3‐kinase complex functions at the trans‐Golgi network (2001, background): “Both Beclin and PtdIns 3-kinase were shown to be required for autophagy (Liang et al., 1999; Petiot et al., 2000).”