| 2006 |
FNIP1 was identified as a direct binding partner of folliculin (FLCN) and also interacts with AMPK. FNIP1 is phosphorylated by AMPK, and this phosphorylation is reduced by AMPK inhibitors, which also reduce FNIP1 expression. FLCN phosphorylation is diminished by rapamycin and amino acid starvation and facilitated by FNIP1 overexpression, placing FNIP1 in the AMPK and mTOR signaling pathways. |
Co-immunoprecipitation, pulldown, in vitro phosphorylation assay, pharmacological inhibition |
Proceedings of the National Academy of Sciences of the United States of America |
High |
17028174
|
| 2008 |
FNIP1 interaction with FLCN is mediated mainly by the C-terminal domains of each protein. Knockdown of FNIP1 decreases S6K1 phosphorylation, indicating that the FLCN-FNIP1 complex positively regulates S6K1 phosphorylation (mTOR signaling). |
Co-immunoprecipitation, siRNA knockdown, western blot for S6K1 phosphorylation |
Oncogene |
Medium |
18663353
|
| 2012 |
Fnip1 knockout mice display a complete block in B cell development at the pre-B cell stage. AMPK and mTOR are dysregulated in Fnip1-null pre-B cells, resulting in excessive cell growth and enhanced apoptosis in response to metabolic stress, establishing Fnip1 as a metabolic checkpoint for B lymphocyte development. |
Genetic knockout mouse model, flow cytometry, immunoglobulin transgene rescue experiment, apoptosis assays |
Immunity |
High |
22608497
|
| 2012 |
Conditional deletion of Flcn in B cells recapitulates the pro-B cell arrest of Fnip1-null mice. The B cell developmental arrest in Fnip1-null mice results from rapid caspase-induced pre-B cell death, and a Bcl2 transgene reconstitutes mature B-cell populations, demonstrating FLCN-FNIP1 complex functions through both mTOR-dependent and independent pathways in B cell differentiation. |
Conditional knockout mice, Bcl2 transgene rescue, caspase activity assays, flow cytometry |
Blood |
High |
22709692
|
| 2014 |
Loss of Fnip1 in mice increases type I slow-twitch muscle fibers, increases AMPK activation, and increases PGC1α expression. Genetic disruption of PGC1α rescues normal levels of type I fiber markers in Fnip1-null mice, placing Fnip1 upstream of AMPK-PGC1α in the control of muscle fiber type specification. |
Knockout mouse model, genetic epistasis (Fnip1 KO × PGC1α KO double mutant), fiber type immunostaining, mitochondrial assays, biochemical analysis |
Proceedings of the National Academy of Sciences of the United States of America |
High |
25548157
|
| 2014 |
Fnip1-null mice show arrest of iNKT cell development at stage 2. Fnip1-null iNKT cells exhibit hyperactive mTOR, reduced mitochondrial number despite lower ATP levels, and increased apoptosis sensitivity, indicating Fnip1 maintains metabolic homeostasis required for iNKT cell maturation. |
Knockout mouse model, flow cytometry, TCR transgene and Bim KO rescue experiments, mitochondrial and metabolic assays |
Proceedings of the National Academy of Sciences of the United States of America |
High |
24785297
|
| 2015 |
Structural analysis of yeast Fnip1/2 orthologue Lst4 confirms it contains a longin domain (first domain of the DENN module), and the Lst7 (folliculin orthologue)/Lst4 complex exists as a 1:1 heterodimer in solution. The Lst4 DENN domain mediates interaction with Lst7. The Lst7/Lst4 complex relocates to the vacuolar membrane in response to nutrient (carbon) starvation. |
Crystal structure, biochemical reconstitution, gel filtration, co-immunoprecipitation, fluorescence microscopy |
Open biology |
High |
26631379
|
| 2016 |
miR-499 directly targets Fnip1 mRNA. Inhibition of Fnip1 reactivates AMPK/PGC-1α signaling and mitochondrial oxidative metabolism in myocytes, establishing a miR-499/Fnip1/AMPK circuit that couples muscle fiber type and mitochondrial function. |
In vivo mouse models, miRNA target validation, siRNA knockdown in myocytes, metabolic assays, mdx mouse model |
EMBO molecular medicine |
High |
27506764
|
| 2016 |
A loss-of-function mutation in Fnip1 causes profound B cell deficiency, and FNIP1-deficient mice develop cardiomyopathy with left ventricular hypertrophy and glycogen accumulation. γ2-specific AMPK activity is elevated in neonatal FNIP1-deficient myocardium, and AMPK-dependent ULK1 phosphorylation and autophagy are increased in FNIP1-deficient B cell progenitors, confirming FNIP1 as a negative regulator of AMPK. |
ENU-mutagenesis mouse model, cardiac phenotyping, kinase activity assays, autophagy assays, BCL2 rescue |
Proceedings of the National Academy of Sciences of the United States of America |
High |
27303042
|
| 2019 |
CK2 phosphorylates FNIP1 on priming serine-938, triggering relay phosphorylation on S939, S941, S946, and S948, which promotes FNIP1 interaction with Hsp90 and leads to incremental inhibition of Hsp90 ATPase activity and gradual activation of Hsp90 client proteins. PP5 dephosphorylates FNIP1, enabling O-GlcNAc addition to S938 that antagonizes phosphorylation, prevents Hsp90 interaction, and promotes FNIP1 ubiquitination at K1119 and proteasomal degradation. |
In vitro phosphorylation assay, mutagenesis of phospho-sites, co-immunoprecipitation, ATPase activity assay, ubiquitination assay, client protein activation assays |
Cell reports |
High |
30699359
|
| 2021 |
FNIP1 controls skeletal muscle mitochondrial oxidative program through AMPK signaling; basal levels of FNIP1 are sufficient to inhibit AMPK but not mTORC1 activity. Surprisingly, FNIP1 actions on type I fiber program are independent of AMPK and its downstream PGC-1α, establishing separable AMPK-dependent and -independent functions of FNIP1. |
Transgenic and knockout mouse models (Fnip1Tg, Fnip1KO, Fnip1TgKO), primary muscle cell assays, genetic epistasis |
PLoS genetics |
High |
33780446
|
| 2021 |
Loss of FLCN or its binding partners FNIP1/FNIP2 in human renal tubular epithelial cells induces an interferon response independently of interferon, with STAT2 recruitment to chromatin and slowed cellular proliferation, identifying STAT1/2 signaling as a novel target downstream of the FLCN-FNIP complex in renal cells. |
CRISPR knockout in RPTEC/TERT1 cells, chromatin immunoprecipitation, transcriptomics, proliferation assays |
eLife |
Medium |
33459596
|
| 2022 |
FNIP1 binds to and promotes the activity of SERCA (the main Ca2+ pump responsible for cytosolic Ca2+ removal) in adipocytes. Loss of FNIP1 results in enhanced intracellular Ca2+ signals and activation of a Ca2+-dependent thermogenic program, establishing FNIP1 as a negative regulator of beige adipocyte thermogenesis through SERCA-Ca2+ dynamics. |
Adipocyte-specific FNIP1 knockout mice, co-immunoprecipitation, Ca2+ imaging, SERCA activity assays, mitochondrial respiration assays, metabolic phenotyping |
The Journal of experimental medicine |
High |
35412553
|
| 2023 |
AMPK directly phosphorylates five conserved serine residues in FNIP1, suppressing the function of the FLCN-FNIP1 complex. FNIP1 phosphorylation by AMPK is required for nuclear translocation of TFEB and TFEB-dependent increases of PGC1α and ERRα mRNAs, linking mitochondrial damage to sequential waves of lysosomal and mitochondrial biogenesis. |
In vitro AMPK phosphorylation assay, phospho-site mutagenesis, TFEB nuclear translocation imaging, transcriptional reporter assays, mitochondrial biogenesis assays |
Science (New York, N.Y.) |
High |
37079666
|
| 2023 |
MEF2A and MEF2D transcription factors directly regulate transcription of FNIP1 and FNIP2. The FLCN-FNIP1/2 complex acts as a GTPase-activating protein (GAP) for RRAGC/RRAGD to promote mTORC1 recruitment to lysosomes and activation. SRC kinase phosphorylates MEF2D, enhancing its transcriptional activity and MTORC1 activation through FNIP1/2 upregulation. |
ChIP, transcriptional reporter assays, knockdown/overexpression, lysosomal fractionation, mTORC1 activity assays |
Autophagy |
Medium |
37772772
|
| 2023 |
Myofiber-specific FNIP1 deficiency stimulates PGC-1α to activate chemokine gene transcription, driving macrophage recruitment and functional muscle angiogenesis independently of AMPK. |
Muscle-specific knockout mouse model, hindlimb ischemia model, macrophage depletion, gene expression analysis, blood flow measurement |
Nature communications |
Medium |
37932296
|
| 2023 |
FNIP1 is a substrate of the FEM1b ubiquitin ligase axis; the FEM1b-FNIP1 interaction is targetable by the small molecule EN106. FNIP1 alters mitochondrial morphology, reduces oxidative phosphorylation, and protects cells from ROS accumulation. |
In vitro experiments in HUVECs, pharmacological inhibition with EN106, cellular ROS and mitochondrial morphology assays |
Bioactive materials |
Low |
37521275
|
| 2024 |
AMPK phosphorylation of FNIP1 at serine-220 (S220) controls mitochondrial electron transfer chain complex assembly, fuel utilization, and exercise performance in skeletal muscle. Using nonphosphorylatable (S220A) and phosphomimetic (S220D) transgenic mouse models, S220 phosphorylation was shown to regulate mitochondrial function independently of mTORC1-TFEB signaling. |
Phospho-site specific transgenic mouse models (S220A/S220D), in vitro AMPK phosphorylation, primary muscle cell biochemistry, exercise performance assays, electron transport chain complex assembly assays |
Science advances |
High |
38324677
|
| 2024 |
Muscle-specific FNIP1 deficiency stimulates nuclear translocation of TFEB, which activates transcription of Igf2 at a conserved promoter-binding site, leading to IGF2 secretion that stimulates osteoclastogenesis through IGF2 receptor signaling, establishing a muscle-bone cross-talk axis. |
Muscle-specific FNIP1 knockout and rescue (AAV9-FNIP1), TFEB ChIP at Igf2 promoter, AAV9-IGF2 overexpression, osteoclast assays, bone phenotyping |
Science translational medicine |
High |
38838134
|
| 2024 |
FNIP1 binds to phosphorylated STAT3 (p-STAT3) and suppresses its expression. Loss of FNIP1 increases STAT3 phosphorylation and nuclear localization, and pharmacological inhibition of p-STAT3 rescues the excessive tumorigenesis caused by FNIP1 deletion in colorectal cancer cells. |
Co-immunoprecipitation, in vivo and in vitro knockout models, STAT3 phosphorylation western blot, nuclear fractionation, p-STAT3 inhibitor rescue |
iScience |
Medium |
39262790
|
| 2024 |
MITF suppresses melanoma mesenchymal phenotype by activating expression of FNIP1, FNIP2, and FLCN, components of the non-canonical mTORC1 pathway, thereby promoting cytoplasmic retention and lysosome-mediated degradation of TFE3. |
Transcriptional reporter assays, TFE3 localization imaging, FNIP1/FNIP2/FLCN expression manipulation in melanoma cell lines |
bioRxivpreprint |
Low |
bio_10.1101_2024.07.11.603140
|
| 2026 |
Fnip1 modulates B cell receptor (BCR) signaling thresholds and metabolic programming by regulating the AMPK/FLCN/TFEB and CD19/PI3K/Akt/mTORC1 pathways, restricting TFEB nuclear access. Loss of Fnip1 in conditional knockout mice causes arrest at the transitional B220+CD93mid stage. |
Conditional knockout mouse model, BCR signaling assays, TFEB nuclear localization imaging, metabolic assays, MD4/mHEL/sHEL tolerance model |
bioRxivpreprint |
Medium |
41959523
|