Lysosomal mTORC2/PHLPP1/Akt Regulate Chaperone-Mediated Autophagy

Arias, Esperanza; Koga, Hiroshi; Díaz, Antonio; Mocholí, Enric; Patel, Bindi; Cuervo, Ana María

doi:10.1016/j.molcel.2015.05.030

Cited by 221 publications

(267 citation statements)

References 36 publications

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“…PFK‐2 has a canonical CMA motif (Dr Ann Maria Cuervo, written communication, May 2016; Figure 6A) that can potentially bind hsc70. It has been recently shown that CMA is regulated by lysosomal‐targeted Akt1 activity in a mammalian target of rapamycin complex (mTORC) 2– and PH domain leucine‐rich repeat protein phosphatase (PHLPP1)–dependent manner (Figure 6B) 27, 28. Specifically, mTORC2 phosphorylates and activates Akt1, thereby decreasing CMA.…”

Section: Resultsmentioning

confidence: 98%

“…A, A schematic of PFK‐2 indicating a putative CMA consensus sequence, catalytic cores, and known phosphorylation sites (starred). B, Lysosomal localized protein kinase B (Akt) 1 is phosphorylated and dephosphorylated by mammalian target of rapamycin complex (mTORC) 2 and PH domain leucine‐rich repeat protein phosphatase (PHLPP) 1, respectively 28. Phosphorylated Akt1 prevents CMA.…”

Section: Resultsmentioning

confidence: 99%

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Cardiac Insulin Signaling Regulates Glycolysis Through Phosphofructokinase 2 Content and Activity

Humphries

Matsuzaki

Vadvalkar

et al. 2017

JAHA

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BackgroundThe healthy heart has a dynamic capacity to respond and adapt to changes in nutrient availability. Diabetes mellitus disrupts this metabolic flexibility and promotes cardiomyopathy through mechanisms that are not completely understood. Phosphofructokinase 2 (PFK‐2) is a primary regulator of cardiac glycolysis and substrate selection, yet its regulation under normal and pathological conditions is unknown. This study was undertaken to determine how changes in insulin signaling affect PFK‐2 content, activity, and cardiac metabolism.Methods and ResultsStreptozotocin‐induced diabetes mellitus, high‐fat diet feeding, and fasted mice were used to identify how decreased insulin signaling affects PFK‐2 and cardiac metabolism. Primary adult cardiomyocytes were used to define the mechanisms that regulate PFK‐2 degradation. Both type 1 diabetes mellitus and a high‐fat diet induced a significant decrease in cardiac PFK‐2 protein content without affecting its transcript levels. Overnight fasting also induced a decrease in PFK‐2, suggesting it is rapidly degraded in the absence of insulin signaling. An unbiased metabolomic study demonstrated that decreased PFK‐2 in fasted animals is accompanied by an increase in glycolytic intermediates upstream of phosphofructokianse‐1, whereas those downstream are diminished. Mechanistic studies using cardiomyocytes showed that, in the absence of insulin signaling, PFK‐2 is rapidly degraded via both proteasomal‐ and chaperone‐mediated autophagy.ConclusionsThe loss of PFK‐2 content as a result of reduced insulin signaling impairs the capacity to dynamically regulate glycolysis and elevates the levels of early glycolytic intermediates. Although this may be beneficial in the fasted state to conserve systemic glucose, it represents a pathological impairment in diabetes mellitus.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Cardiac Insulin Signaling Regulates Glycolysis Through Phosphofructokinase 2 Content and Activity

Humphries

Matsuzaki

Vadvalkar

et al. 2017

JAHA

View full text Add to dashboard Cite

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“…It is thus possible that different transcription factors co-exist to assure proteostasis under several circumstances and in distinct cell types. In fact, levels of basal CMA activity and the amplitude of the induction varies among different cell types [12,16,36,37]. Importantly, this novel NFE2L2-LAMP2A axis is conserved in different cell types.…”

Section: Discussionmentioning

confidence: 99%

“…This step was repeated twice to wash the lysosomal-enriched fraction. Lysosomes active for CMA were isolated by centrifugation of the lysosomal-enriched fraction (light mitochondria and lysosomes) in a discontinuous metrizamide (AK Scientific, 69,696) density gradient [37,56]. The fraction of broken lysosomes at the moment of isolation was measured using the HEX/β-hexosaminidase latency assay [57].…”

Section: Methodsmentioning

confidence: 99%

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Transcription factor NFE2L2/NRF2 modulates chaperone-mediated autophagy through the regulation of LAMP2A

et al. 2018

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Chaperone-mediated autophagy (CMA) is a selective degradative process for cytosolic proteins that contributes to the maintenance of proteostasis. The signaling mechanisms that control CMA are not fully understood but might involve response to stress conditions including oxidative stress. Considering the role of CMA in redoxtasis and proteostasis, we sought to determine if the transcription factor NFE2L2/NRF2 (nuclear factor, erythroid derived 2, like 2) has an impact on CMA modulation. In this work, we identified and validated 2 NFE2L2 binding sequences in the LAMP2 gene and demonstrated in several human and mouse cell types that NFE2L2 deficiency and overexpression was linked to reduced and increased LAMP2A levels, respectively. Accordingly, lysosomal LAMP2A levels were drastically reduced in nfe2l2-knockout hepatocytes, which also displayed a marked decrease in CMA activity. Oxidant challenge with paraquat or hydrogen peroxide, or pharmacological activation of NFE2L2 with sulforaphane or dimethyl fumarate also increased LAMP2A levels and CMA activity. Overall, our study identifies for the first time basal and inducible regulation of LAMP2A, and consequently CMA activity, by NFE2L2.Abbreviations: ACTB: actin, beta, ARE: antioxidant response element; ATG5: autophagy related 5; BACH1: BTB domain and CNC homolog 1; ChIP: chromatin immunoprecipitation; CMA: chaperone-mediated autophagy; DHE: dihydroethidium; DMF: dimethyl fumarate; ENCODE: Encyclopedia of DNA elements at the University of California, Santa Cruz; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GBA: glucosylceramidase beta; GFP: green fluorescent protein; HMOX1: heme oxygenase 1; H2O2: hydrogen peroxide; HSPA8/HSC70: heat shock protein family A (Hsp70) member 8; KEAP1: kelch like ECH associated protein 1; LAMP2A: lysosomal associated membrane protein 2A; LAMP2B: lysosomal associated membrane protein 2B; LAMP2C: lysosomal associated membrane protein 2C; LAMP1: lysosomal associated membrane protein 1; MAFF: MAF bZIP transcription factor F; MAFK: MAF bZIP transcription factor K; NFE2L2/NRF2: nuclear factor, erythroid derived 2, like 2; NQO1: NAD(P)H quinone dehydrogenase 1; PQ: paraquat; PI: protease inhibitors; qRT-PCR: quantitative real-time polymerase chain reaction; RNASE: ribonuclease A family member; SFN: sulforaphane; SQSTM1/p62: sequestosome 1; TBP: TATA-box binding protein

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The mTOR–lysosome axis at the centre of ageing

et al. 2021

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Age‐related diseases represent some of the largest unmet clinical needs of our time. While treatment of specific disease‐related signs has had some success (for example, the effect of statin drugs on slowing progression of atherosclerosis), slowing biological ageing itself represents a target that could significantly increase health span and reduce the prevalence of multiple age‐related diseases. Mechanistic target of rapamycin complex 1 (mTORC1) is known to control fundamental processes in ageing: inhibiting this signalling complex slows biological ageing, reduces age‐related disease pathology and increases lifespan in model organisms. How mTORC1 inhibition achieves this is still subject to ongoing research. However, one mechanism by which mTORC1 inhibition is thought to slow ageing is by activating the autophagy–lysosome pathway. In this review, we examine the special bidirectional relationship between mTORC1 and the lysosome. In cells, mTORC1 is located on lysosomes. From this advantageous position, it directly controls the autophagy–lysosome pathway. However, the lysosome also controls mTORC1 activity in numerous ways, creating a special two‐way relationship. We then explore specific examples of how inhibition of mTORC1 and activation of the autophagy–lysosome pathway slow the molecular hallmarks of ageing. This body of literature demonstrates that the autophagy–lysosome pathway represents an excellent target for treatments that seek to slow biological ageing and increase health span in humans.

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Lysosomal mTORC2/PHLPP1/Akt Regulate Chaperone-Mediated Autophagy

Cited by 221 publications

References 36 publications

Cardiac Insulin Signaling Regulates Glycolysis Through Phosphofructokinase 2 Content and Activity

Cardiac Insulin Signaling Regulates Glycolysis Through Phosphofructokinase 2 Content and Activity

Transcription factor NFE2L2/NRF2 modulates chaperone-mediated autophagy through the regulation of LAMP2A

The mTOR–lysosome axis at the centre of ageing

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