AMPK targets PDZD8 to promote carbon source shift to glutamine
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus Musculus
SUBMITTER: 
Shengcai Lin
PROVIDER: PXD041428 | iProX | Thu Apr 06 00:00:00 BST 2023
REPOSITORIES: iProX
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Project description:5’-AMP-Activated Protein Kinase (Ampk) is an energy gatekeeper that responds to decreases in available ATP by inhibiting energy-consuming processes like protein synthesis and promoting energy-generating processes like glucose uptake. Recently, our lab showed that Lkb1, a previously unstudied kinase in B cell immunology and the main upstream kinase of Ampk, had a critical and unexpected role in B cell activation and germinal center formation. In T cells knockout of the downstream target Ampk, only partially phenocopies Lkb1 deletion, so we sought to determine whether the role of Lkb1 in B cells depends on Ampk. We find Ampk is activated upon B cell stimulation in vitro. Surprisingly, however, Ampk activation occurs in the absence of energetic stress, and B cells continue to grow and divide despite Ampk activity. We performed an IP-MS substrate screen to identify Ampk targets and only identified a limited repertoire of canonical targets, and many non-canonical targets. Despite activation of Ampk and the major role of Lkb1 in B cell activation, B cell specific deletion of Ampk does not significantly affect B cell activation, differentiation, carbon handling, gene expression, or humoral immune responses. The only major effect of Ampk loss was accelerated downregulation of IgD during stimulation, which was preceded by downregulation of the IgD regulator Zfp318. Early activation of Ampk by pharmacological means also has little impact on B cell function, although treatment with the biguanide Phenformin critically impairs germinal center formation and class switch recombination in vivo, but does not significantly impair antigen-specific antibody responses. Combined, our results suggest an unexpected and unexplained activation of Ampk in B cells.
2019-06-16 | GSE121025 | GEO
Project description:Mitochondrial quality control failure is frequently observed in neurodegenerative diseases. The detection of damaged mitochondria by stabilization of PTEN-induced kinase 1 (PINK1) requires transport of Pink1 mRNA by tethering it to the mitochondrial surface. Here, we report that inhibition of AMPK by activation of the insulin signaling cascade prevents Pink1 mRNA binding to mitochondria. Mechanistically, AMPK phosphorylates the RNA anchor complex subunit SYNJ2BP within its PDZ domain, a phosphorylation site that is necessary for its interaction with the RNA-binding protein SYNJ2. Interestingly, loss of mitochondrial Pink1 mRNA association upon insulin addition is required for PINK1 protein activation and its function as a ubiquitin kinase in the mitophagy pathway, thus placing PINK1 function under metabolic control. Induction of insulin-resistance in vitro by the key genetic Alzheimer-risk factor apolipoprotein E4 retains Pink1 mRNA at the mitochondria and prevents proper PINK1 activity especially in neurites. Our results thus identify a metabolic switch controlling Pink1 mRNA localization and PINK1 activity via insulin and AMPK signaling in neurons and propose a mechanistic connection between insulin resistance and mitochondrial dysfunction.
2024-02-23 | PXD045621 | Pride
Project description:Purpose: Mutations in STK11 (LKB1) occur in 17% of lung adenocarcinoma (LUAD) and drive a suppressive (cold) tumor immune microenvironment (TME) and resistance to immunotherapy. The mechanisms underpin the establishment and maintenance of a cold TME in LKB1 mutant LUAD remain poorly understood and the identification of downstream effectors is critical to inform therapeutic strategies to invigorate antitumor immunity. In this study, we investigated the association between inactivation of AMPK, one of the downstream substrates of LKB1, and immune evasion in human LUAD as well as the causal role of AMPK on TME in genetically engineered mouse model (GEMM) of LUAD. Experimental Design: We modeled AMPK inactivation in vivo using GEMM by deleting both AMPKα1 (Prkaa1) and AMPKα2 (Prkaa2) in KrasG12D-driven LUAD (KAA). Furthermore, we investigated the impact of AMPK inactivation on immune cell infiltration and global gene-expression programs of murine LUAD. Gene expression signature from AMPK-deficient murine LUAD was further compared to that of Lkb1 deficient murineLUAD as well as human LUAD with either LKB1 mutation or attenuated AMPK phosphorylation. Results: Inactivation of both AMPKα1 and AMPKα2 accelerates KrasG12D-driven LUAD. AMPK-deficient tumors are characterized with reduced infiltration of CD8+/CD4+ T cells and gene signatures associated with compromised immune microenvironment, which resembles LKB1-deficient murine and human LUAD (KL) as well as LKB1-wildtype LUAD with reduced AMPK phosphorylation. Attenuation of the MHC Class 1 component ß2 microglobulin (ß2M) was identified as a shared feature in KL and KAA murine LUAD as well as in human LUAD with either LKB1 mutations or reduced AMPK phosphorylation. Furthermore, reactivation of AMPK by expression of constitutive active form of AMPKα1 leads to restoration of ß2M level in LKB1 mutant LUAD cells. Conclusions: The results identify attenuation of the LKB1 substrate AMPK as an important mechanism for decreased MHC Class 1 expression and immune evasion in LKB1 mutant LUAD. Translational relevance: LKB1 loss-of-function mutations rank as the third most common genetic alterations found in lung adenocarcinoma and associated with immune evasion. In the current study, on the basis of GEMM of LUAD we established the causal relationship between inactivation of the LKB1 substrate AMPK and immune evasion. Furthermore we find that the status of AMPK phosphorylation is more sensitive than LKB1 mutation in predicting impaired tumor immune microenvironment and likely also for the resistance to immunotherapy. The results also suggest that restoration of AMPK activity could increase the number of patients benefiting from immunotherapy.
2022-01-26 | GSE175479 | GEO
Project description:AMP-activated protein kinase (AMPK) is a major regulator of cellular energy homeostasis that coordinates metabolic pathways in order to balance nutrient supply with energy demand. AMPK elicits acute and diverse metabolic effects by directly phosphorylating various targets. AMPK activation also promotes metabolic reprogramming in longer term via effects on gene expression. The aim of this study is to elucidate molecular mechanism(s) by which AMPK activation modulates metabolic adaptation through its impact on gene regulation.
2019-03-04 | GSE104170 | GEO
Project description:We investigated the potential role of AMPK in the phosphorylation of ORP8.In vitro kinase assay using purified ORP8 and kinase-active AMPK complex confirmed that ORP8 is the direct substrate of AMPK. Phosphorylated ORP8 from in vitro kinase assay was analyzed by HPLC-MS/MS.
2023-10-24 | PXD036201 | Pride
Project description:Deletion of AMPK significantly extended the onset of leukemogenesis and depleted leukemia initiating cells (LICs). To identify how AMPK regulates LICs, we performed gene expression profiling of LICs isolated from AMPK wild type leukemic mice or AMPK-deficient leukemic mice. 4 groups were analyzed; 1) Whole leukemia (GFP+) from AMPK WT ( AMPKfl/fl) mice, 2) Whole leukemia (GFP+) from AMPK-deficient ( AMPK?/?l) mice, 3) LICs=L-GMP (GFP+,lin-,c-kit+, CD16/32+,CD34+) cells from AMPK WT ( AMPKfl/fl) mice, 4) LICs=L-GMP (GFP+,lin-,c-kit+, CD16/32+,CD34+) cells from AMPK-deficient ( AMPK?/?l) mice.
2015-01-01 | E-GEOD-64602 | biostudies-arrayexpress
Project description:Hypoxia is a hallmark of solid tumors. Mitochondria play essential roles in cellular adaptation to hypoxia, but the underlying mechanisms are not fully understood. Through mitochondrial proteomic profiling, we find that the prolyl hydroxylase EglN1 accumulates on mitochondria under hypoxia. EglN1 substrate binding region 23 loop is responsible for its mitochondrial translocation and contributes to tumor growth. Furthermore, we identify AMPK as an EglN1 substrate on mitochondria. The EglN1-AMPK interaction is essential for their mutual mitochondrial translocation. EglN1 prolyl-hydroxylates AMPK under normoxia, then they rapidly dissociate following prolyl-hydroxylation, leading to their immediate release from mitochondria. While hypoxia results in constant EglN1-AMPK interaction and accumulation on mitochondria, leading to the formation of CaMKK2-EglN1-AMPK complex to activate AMPK phosphorylation, consequently ensuring metabolic homeostasis and tumor growth. Our findings demonstrate EglN1 as an oxygen-sensitive metabolic checkpoint signaling hypoxic stress to mitochondria through its 23 loop, revealing a therapeutic target for solid tumors.
2023-08-29 | PXD041653 | Pride
Project description:Energy homeostasis plays a key role in retarding aging, and mitochondria are responsible for energy production.AMPK plays a central role in maintaining energy homeostasis and mitochondrial homeostasis, and commands autophagy, a clearing and recycling process to maintain cellular homeostasis. However, the effect of AMPK activators on kidney aging has not been fully elucidated. We testified the effects of O304, a novel direct AMPK activator, in naturally aging mice model and D-galactose (D-gal)-treated renal tubular cell culture. We identified that O304 perfectly protects against cellular senescence and aged-related fibrosis in kidneys. Also, O304 restored energy metabolism, promoted autophagy, and preserved mitochondrial homeostasis. Transcriptomic sequencing also proved that O304 induced fatty acid metabolism, mitochondrial biogenesis and ATP process, and downregulated cell aging, DNA damage response and collagen organization. All these results suggest that O304 has a strong potential to retard aged kidney injury through regulating AMPK-induced multiple pathways.
2022-01-27 | GSE192512 | GEO
Project description:Faithful execution of developmental programs relies on the acquisition of unique cell identities from pluripotent progenitors, a process governed by combinatorial inputs from numerous signaling cascades that ultimately dictate lineage-specific transcriptional outputs. Despite growing evidence that metabolism is integrated with many molecular networks, how pathways that control energy homeostasis may affect cell fate decisions is largely unknown. Here, we show that AMPK, a central metabolic regulator, plays critical roles in lineage specification. Although AMPK-deficient embryonic stem cells (ESCs) were normal in the pluripotent state, these cells displayed profound defects upon differentiation, failing to generate chimeric embryos and preferentially adopting an ectodermal fate at the expense of the endoderm during embryoid body (EB) formation. AMPK-/- EBs exhibited reduced levels of Tfeb, a master transcriptional regulator of lysosomes, leading to diminished endolysosomal function. Remarkably, genetic loss of Tfeb also yielded endodermal defects, while AMPK-null ESCs over-expressing this transcription factor normalized their differential potential, revealing an intimate connection between Tfeb/lysosomes and germ layer specification. The compromised endolysosomal system resulting from AMPK or Tfeb inactivation blunted Wnt signaling, while up-regulating this pathway restored expression of endodermal markers. Collectively, these results uncover the AMPK pathway as a novel regulator of cell fate determination during differentiation. 2 WT and 2 AMPK DKO ESC lines were differentiated into embryoid bodies (EBs) for various lengths of time (2, 4, 8, and 12 days) in high and low glucose conditions. Both ESC and EB samples were profiled by mRNA-seq to examine how global gene expression changes associated with ESC differentiation are affected by AMPK deletion.
2016-03-09 | E-GEOD-77705 | biostudies-arrayexpress
Project description:The AMP-activated protein kinase (AMPK) is a master sensor of the cellular energy status and is crucial for the adaptive response to limited energy availability. AMPK is implicated in the regulation of many cellular processes, including autophagy. However, the precise mechanisms by which AMPK controls these processes and the identities of relevant substrates are not fully understood. With a protein microarrays we identified Cyclin Y as novel AMPK substrate that is phosphorylated at S326 both in vitro and in cells. Phosphorylation of Cyclin Y at S326 promotes its interaction with the cyclin-dependent kinase 16 (CDK16), thereby stimulating its catalytic activity. When expressed in cells, Cyclin Y/CDK16 is sufficient to promote autophagy. Moreover, Cyclin Y/CDK16 is necessary for efficient AMPK-dependent activation of autophagy. This functional interaction is mediated by AMPK phosphorylating S326 of Cyclin Y. Collectively, we define Cyclin Y/CDK16 as downstream effector of AMPK for inducing autophagy.
2020-02-17 | PXD009968 | Pride