Life Science Alliance

Special AT-rich binding protein 1 (SATB1) is a nuclear matrix-associated transcription factor that orchestrates higher-order chromatin architecture and gene expression in T and B lymphocytes. While SATB1s role in T cells is well-established, its regulation and function in B cells remain underexplored. Here, we showed that Satb1 expression in mature B cells is controlled by alternative promoter usage and splicing, with promoters P1 and P3 dynamically switching upon LPS-induced activation, while P2 remains transcriptionally silent. We identified four Satb1 mRNA isoforms, including two novel transcripts ({Delta}9 and{Delta} 9{Delta}11), all of which maintain open reading frames. Satb1 transcription decreases upon activation while SATB1 protein content evolves differently, suggesting post-transcriptional regulation. SATB1 forms a high-molecular-weight complex in B cells, and co-immunoprecipitation mass spectrometry reveals RNA-binding proteins as its predominant interactors. These findings specify SATB1 expression kinetics during B-cell activation and reveal its role as a regulator of RNA splicing in B cells.

Leucine-rich repeat kinase 2 (LRRK2) is a complex multidomain protein whose catalytic and protein-protein interaction domains regulate a wide range of cellular processes. To investigate whether evolutionary divergence of these domains contributes to species-specific differences in LRRK2 biology, we combined phylogenetic, sequence, interactome and structural analyses of human and mouse LRRK2. Phylogenetic analysis revealed that the catalytic core predates the acquisition of the N-terminal and C-terminal protein-protein interaction domains during LRRK2 evolution. Accordingly, despite the high overall sequence similarity between human and mouse LRRK2, sequence divergence was not uniformly distributed across the protein but was concentrated within protein-protein interaction domains, whereas the catalytic ROC-COR- kinase core displayed markedly higher conservation. Consistent with this pattern, comparison of curated human and mouse interactomes revealed substantial differences in protein interaction networks and associated biological pathways. Structural modelling of a subset of interactors further showed that predicted interaction interfaces are enriched for residues that differ between the two species, providing a structural rationale for altered interaction specificity. Together, these findings support the view that evolutionary divergence of LRRK2 protein-protein interaction domains contributes to species-specific interactome organization. These results provide an evolutionary framework for interpreting differences between human and mouse LRRK2 and highlight the importance of considering species-specific interaction networks when translating findings from experimental models.

LIM kinases, LIMK1 and LIMK2, play a crucial role in cytoskeleton dynamics. They are involved in many physiological processes but also in several pathologies such as cancer, neuronal diseases and neurofibromatosis. Although LIM kinases appear as promising therapeutic targets, they remain undruggable. A better understanding of their activity and regulation is thus required to better design efficient targeted therapies. Here, we have shown the impact of a single amino acid on LIMK activity on cofilin, their main substrate in actin filament remodelling. We demonstrated that Y632 and Y630, for LIMK1 and LIMK2 respectively, mediate LIMK dimerization, resulting in their transphosphorylation. This process seems to be a prerequisite for their canonical phosphorylation on their respective T508 and T505 residues within the activation loop. These Tyrosine are not phosphorylated, their aromatic nature is rather critical to ensure proper LIMK activity on cofilin. These results bring new insights into LIMK molecular features.

Pigmentation is a critical protective mechanism that safeguards the skin against UV-induced damage, whereas dysregulated pigmentation predisposes to pigmentary disorders and skin malignancies. Although calcium signaling has emerged as an important regulator of melanogenesis, the identity of the calcium-handling proteins and the molecular mechanisms linking calcium dynamics to pigmentation remain poorly understood. Here, we identify the ER calcium pump SERCA2b as a negative regulator of pigmentation through modulation of ER stress and mitochondrial calcium uptake. We demonstrate that SERCA2b expression inversely correlates with pigmentation levels, and gain- and loss-of-function studies establish SERCA2b as a suppressor of melanogenesis. Mechanistically, SERCA2b depletion induces adaptive ER stress, enhances ER-mitochondrial proximity, and promotes mitochondrial calcium uptake. Notably, mutations in SERCA2b are associated with Darier disease, a condition characterized by hyperpigmented skin lesions, although the underlying mechanism remains unknown. To address this, we generated SERCA2b mutants corresponding to variants identified in Indian Dariers disease patients and examined their effects on pigmentation, ER stress, and mitochondrial calcium dynamics. The mutant phenotypes closely recapitulated SERCA2b loss-of-function effects, demonstrating that adaptive ER stress and enhanced mitochondrial calcium signaling underlie hyperpigmentation associated with Dariers disease. Importantly, treatment with 4-phenylbutyrate (4-PBA), an FDA-approved ER stress alleviator, rescued mutant-induced hyperpigmentation, reduced ER stress, and normalized mitochondrial calcium uptake. Collectively, our findings uncover a previously unrecognized role of SERCA2b in skin pigmentation, establish a mechanistic link between SERCA2b mutations and hyperpigmentation, and identify adaptive ER stress pathways as potential therapeutic target for pigmentary disorders.

Cyclin-dependent kinases (CDKs) control eukaryotic cell-cycle progression by phosphorylating specific substrates with substrate recognition often involving cyclin-specific docking interactions. However, in minimal cell cycle control systems driven by a single cyclin-CDK complex, how docking interactions contribute to the differential timing of substrate phosphorylation remains unclear. Here, we used AlphaFold-Multimer to systematically predict interactions between the fission yeast mitotic cyclin-CDK fusion Cdc13-L-Cdc2 and its known in vivo CDK substrates. We found that many substrates are predicted to interact with the cyclin hydrophobic patch, and have identified a previously uncharacterised docking motif, [FVIPWGLAM](x)xER[LMV] (ERL motif), with features consistent with an atypical RxL motif. We show that ERL motifs can functionally substitute for canonical RxL motifs to promote phosphorylation of a model CDK substrate by Cdc13-Cdc2, while the S-phase cyclin-CDK Cig2-Cdc2 was found to preferentially phosphorylate substrates containing canonical RxL motifs. Finally, we investigated whether Cdc13-L-Cdc2 is predicted to preferentially bind DNA replication substrates over mitotic substrates but found no evidence of differential binding. These results reveal diversity in cyclin-CDK substrate recognition beyond established docking motifs.

Protein homeostasis - i.e., proteostasis - is the biological process by which the qualitative and quantitative balance of the proteome is conducted, either by preserving functionally relevant proteins or by degrading unnecessary ones. Stress conditions can modulate cellular proteostasis in order to promote cytoprotection and preserve the viability of living organisms. Among the cellular pathways already described that can play an important role in preserving biological functions by modulating proteostasis are the heat shock response and the ribosome quality control pathways. In this work, we show that the Rqc1p protein is necessary for the thermoadaptation of S. cerevisiae to heat shock, as RQC1-deficient yeast is sensitive to elevated temperatures. In silico approaches - such as multiple sequence alignment, structural analysis, and molecular dynamics simulations - confirmed earlier predictions that Rqc1p shares characteristics with the bHLH family of proteins. We also verified, through computational prediction of sub-cellular localization, that S. cerevisiae Rqc1p contains nuclear localization signals, suggesting that this protein can potentially be translocated toward the nucleus, thereby broadening its current range of recognized biological functions in this organism. Also, analysis of yeast transcriptomes subjected to heat shock showed that Rqc1p mRNA levels do not fluctuate in response to heat shock, suggesting that cellular concentrations of Rqc1p are already at optimal levels to elicit a rapid and effective response during thermal stress in S. cerevisiae.

RASAL3 acts as a negative regulator of small cellular GTPases in hematopoietic cells. In immune cells, it primarily modulates the RAS/MAPK signaling pathway and affects cellular events including proliferation, differentiation, survival, and migration. Due to its inhibitory role in T cells, RASAL3 may represent a potential modulatory target for improving therapeutic strategies such as cell-based immunotherapy. However, most existing knowledge about RASAL3 function is derived from murine models, and its role in human T-cell signaling remains insufficiently characterized. To address this gap, we systematically investigated the function of RASAL3 in human primary T cells and T-cell line. For this purpose, we employed RASAL3 overexpression, CRISPR/Cas9-mediated deletion, and siRNA-mediated knockdown to thoroughly analyze the effects of RASAL3 on T-cell signaling, proliferation, and migration. Our data demonstrate that RASAL3 modulates primarily CDC42 and RAC1/RAC2 GTPases activity, SAPK/JNK phosphorylation, c-Fos and c-Jun expression, and IL-2 gene promoter activation. In addition, RASAL3 regulates actin polymerization and T-cell migration. Notably, loss of RASAL3 increases Jurkat T cells motility in vivo and potentiates their homing to the spleen. Collectively, these findings identify RASAL3 as an important regulator of human T-cell activation and motility and highlight its application potential for improving CAR-T cell therapy.

T cell activation is dependent on calcineurin signalling, yet how this pathway integrates with other regulatory systems remains incompletely understood. Here, we exploit the dual pharmacology of FK506, which inhibits calcineurin while also releasing FKBP12-mediated repression of BMP receptors, to dissect signalling crosstalk during T cell responses. A comparative genome-wide CRISPR knockout screen using FK506 and Cyclosporin A revealed that FK506 uniquely engages BMP pathway components and ubiquitin regulatory networks. Functional analyses in Jurkat and primary human T cells showed that FK506 induces BMP receptor-dependent activation of SMAD1/5/8 and triggers a rapid remodelling of K48- and K29-linked ubiquitin chains. Proteomics further demonstrated selective ubiquitination of immune signalling proteins and ubiquitin regulators, linking BMP pathway activation to proteasome-dependent turnover and non-proteolytic ubiquitin signalling. In primary T cells, BMP receptor signalling enhance calcineurin-driven activation, while changes in ubiquitin conjugation modulate this response, thereby establishing an integrated calcineurin-BMP-ubiquitin relay. Together, our results uncover a context-dependent signalling axis in which BMP activation and ubiquitin dynamics fine-tune calcineurin-mediated T cell signalling.

The conversion of transcriptionally silent GGAA microsatellites (GGAASats) into functional enhancers by FET::ETS oncogenic fusions is a hallmark of Ewing sarcoma. However, emerging evidence implicates non-fused, full-length oncogenic ETS transcription factors in activating these repeats in other malignancies. Evaluating the in vivo transcriptional requirements of various human ETS factors in Drosophila, we found that human ETV4 uniquely binds and robustly activates GGAASats in a tissue-specific manner. This activation is strongly inhibited by the human ETS repressor ETV6. Taking advantage of low genetic redundancy in Drosophila, we identified Cabeza (Caz), the single fly FET orthologue, as a necessary cofactor for ETV4-mediated transcription at GGAASats. Conversely, EWS::FLI1-mediated transcriptional activation of GGAASats is entirely independent of endogenous Caz, highlighting the distinct mechanics of covalent tethering versus non-covalent physical complexes. Collectively, our findings provide definitive in vivo evidence that non-fused ETS factors cooperate with endogenous FET proteins to drive transcription from silent GGAA repeats, mechanistically validating this regulatory transformation known to operate as an oncogenic mechanism beyond Ewing sarcoma.

Amyotrophic lateral sclerosis (ALS) is categorized by TDP-43 proteinopathy, however, the nuclear pathological events remain poorly defined. While cytoplasmic TDP-43 inclusions dominate the late disease stages, accumulating evidence indicates that nuclear TDP-43 assemblies arise earlier and impair RNA splicing. Here, we characterized a single RRM-proximal TDP-43 variant, G148V, designed to disrupt nucleic-acid engagement without altering canonical RNA-binding residues. Structural and biophysical analyses revealed conformational changes and loss of DNA/RNA binding. In mammalian cells, TDP-43 G148V robustly formed nuclear puncta with high penetrance, exhibiting solid-like properties, pathological phosphorylation, splicing dysfunction, and toxicity. Furthermore, we identified molecular chaperone HSC70 as an important regulator of the nuclear puncta assembly. HSC70 redistributed into G148V nuclear puncta to modulate their material state, whereas HSC70 depletion significantly promoted puncta solidification, increased insoluble TDP-43 accumulation, and enhanced cytotoxicity. Disease-associated K181E and K263E mutants also formed nuclear puncta and induced HSC70 nuclear redistribution. These findings establish G148V as a model of early nuclear TDP-43 pathology and highlight HSC70-mediated regulation as a key factor of TDP-43 nuclear assembly. HighlightsO_LIA single TDP-43 mutation, G148V, in RRM1 domain robustly induces nuclear puncta without exogenous stress. C_LIO_LIG148V disrupts nucleic-acid binding, driving solid-like nuclear assemblies with hyperphosphorylation. C_LIO_LINuclear G148V puncta impair splicing regulation and reduce cell viability, recapitulating early ALS pathology. C_LIO_LIThe molecular chaperone HSC70 modulates puncta material states and mitigates G148V-associated cytotoxicity. C_LI Graphical abstrac O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC="FIGDIR/small/739729v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@d019c8org.highwire.dtl.DTLVardef@4ca632org.highwire.dtl.DTLVardef@331fd9org.highwire.dtl.DTLVardef@6fe8e4_HPS_FORMAT_FIGEXP M_FIG C_FIG eTOC blurbA structure-guided TDP-43 G148V mutation reveals how loss of nucleic-acid engagement promotes early nuclear condensation, splicing dysfunction, and toxicity, while uncovering a protective role for HSC70 in regulating condensate properties during ALS pathogenesis.

Actin-related protein T2 (ACTRT2) localizes to the perinuclear theca (PT) of male germ cells, yet its functional significance remains unclear. ACTRT2 is evolutionarily conserved and exhibits significant sequence similarity to other testis-specific actin-related proteins, with the highest conservation observed within the canonical actin core domain. We generated Actrt2-deficient mice which displayed male subfertility with pronounced acrosomal malformations originating during the Cap phase of acrosome biogenesis. Actrt2-deficient male mice showed reduced fertilization rate and poor blastocysts quality. Co-immunoprecipitation identified ACTRT2 interactions with PT proteins ACTRT1, ACTRT3, ACTL7A, ACTL9, PFN3, SPEM2 and CCIN while the interaction with CYLC1 was not detected. ACTRT2 overexpression in HEK293T cells altered cell morphology and F-actin distribution. Further, cytoskeletal regulator CFL1 was enriched in testis from Actrt2-deficient mice. We propose that ACTRT2 is a structural component of the PT stabilizing the acroplaxome during spermiogenesis and acrosome biogenesis by modulating actin dynamics. Finally, the high degree of sequence conservation and similarity with ACTRT1 and ACTRT3 together with their similar phenotypes when deleted, indicate that ACTRT2 shares a partial functional redundancy and compensatory capacity with other Arp proteins in testis. Taken together, these findings establish ACTRT2 as a structural regulator of sperm head architecture and male fertility in mice.

Centrioles are highly organised microtubular scaffolds which grow and mature progressively during successive cell cycles. Their molecular organisation is extensively characterized, yet the contribution of several components to centriole assembly, maturation or stability is incompletely understood. Here, using ultrastructure expansion microscopy and transmission electron microscopy, we show that ALMS1, the protein mutated in Alstrom syndrome, is required for proper centriole architecture. In absence of ALMS1, RPE1 cells exhibit shorter centrioles with defects in the microtubular wall, including broken or missing triplets or open B/C tubules. These structural defects arise after procentriole assembly. We show that ALMS1 loss selectively reduces the proximal region proteins CCDC77 and CEP44, leaving intact central and distal ones. ALMS1 is further required for the recruitment of the proximal CEP135 cap and the clearance of the {gamma}-tubulin/GCP2 pool present at the procentriole base. Our findings thus identify ALMS1 as a key organiser of the centriole proximal domain and required for remodelling and stabilising the proximal end of centrioles during cell cycle progression.

BackgroundThe MAPK signalling network coordinates opposing cell fates -- proliferation versus apoptosis -- by combining the activities of ERK, JNK, and p38 kinases in patterns that depend on upstream MAP3K identity. Using multiplexed kinase translocation reporter (KTR) biosensors and functional assays in MCF10A mammary epithelial cells, Peterson et al. (Cell Systems, 2023) demonstrated that MAP3Ks co-activating ERK and JNK drive approximately tenfold more cell cycle entry than MAP3Ks activating ERK alone, and that both kinase activities are independently required for this proliferative response. The transcriptional mechanism underlying this quantitative difference was not identified in the original study. ResultsWe performed a systematic computational re-analysis of the RNA-seq data deposited by Peterson et al. (GEO: GSE213882), encompassing thirteen MAP3K perturbations in doxycycline-induced MCF10A mammary epithelial cells. Based on signalling responses reported by Peterson et al., MAP3Ks were grouped into ERK-only (RAF1, COT) or ERK+JNK co-activating kinases (MLK1, MLK3, ZAK, TAK1, MEKK2, MEKK3). This stratification identified JNK co-activation as the feature most strongly associated with E2F/MYC transcriptional polarity. ERK-only MAP3Ks showed negative enrichment of E2F TARGETS, G2M CHECKPOINT, and MYC TARGETS Hallmark gene sets, whereas ERK+JNK MAP3Ks showed positive enrichment (each MAP3K individually FDR < 0.05 by GSEA). Consistently, inferred activities of E2F1, E2F2, E2F4, and MYC shifted from negative mean ULM t-scores in the ERK group to strongly positive values in the ERK+JNK group (FDR < 0.05 using the CollecTRI regulon). The observed E2F/MYC polarity was robust to alternative transcription factor inference strategies, being reproduced using the DoRothEA A+B regulon and the multivariate model (MLM) framework (Pearson r = 0.77). The signal remained stable under leave-one-out sensitivity analysis and was independently reproduced in MAP3K overexpression signatures from the LINCS L1000 atlas (GEO: GSE92742). ConclusionsERK activation alone was associated with repression of E2F/MYC transcriptional programmes, whereas JNK co-activation was associated with their activation. These opposing transcriptional states provide a potential explanation for the [~]10-fold differences in cell cycle entry reported by Peterson et al. and supports a model in which pRb/E2F regulation integrates combinatorial MAPK co-activation states beyond the canonical ERK-cyclin D-CDK4/6 axis.

Src family kinases (SFKs) share highly conserved catalytic domains yet display distinct biological functions, raising the question of how substrate specificity is achieved. Here, we investigate the molecular basis of differential ITAM recognition by Lck and Src, combining cellular assays with structural analysis and docking simulations. In-cell assays demonstrated that, contrary to Lck, Src was completely incapable of phosphorylating the TCR ITAMs when ectopically expressed in a T cell environment. Domain-swapping experiments further revealed that substitution of the Src kinase domain with that of Lck was sufficient to confer ITAM phosphorylation and trigger downstream TCR signaling responses, whereas exchange of adaptor domains had minimal effect. Comparative structural analysis revealed that, despite their overall conserved fold, Lck exhibits a more open and solvent accessible pocket located between the N- and C-lobes of the kinase domain, adjacent to the activation loop, compared to Src. Consistent with this, docking simulations showed that Lck accommodates ITAM peptides in multiple favourable conformations, whereas Src displays a markedly reduced number of non-productive binding poses. Residue-level contact analysis identified a defined interaction surface in Lck, spanning the inter-lobal regions and activation loop. Our results highlight the importance of kinase domain conformational landscape in shaping substrate selectivity and have implications for the rational design of selective SFK inhibitors.

Early T cell activation induces extensive remodeling of the cellular transcriptome and proteome. We previously showed using a transcriptome-wide crosslinking approach that human translation initiation factor eIF3 directly interacts with a select set of immune-related mRNAs shortly after T cell activation. We also found that eIF3 binding to the 3'-untranslated regions (3'-UTRs) of the TCRA and TCRB mRNAs encoding the T cell receptor alpha and beta subunits dynamically regulates a burst in their translation. MicroRNAs (miRNAs) add an additional layer of regulation by fine-tuning both mRNA and protein expression. Although miRNA expression is dynamically regulated during T cell activation, how miRNAs interact with core regulatory pathways in primary T cells remains poorly understood. Here, we reexamined the eIF3-RNA crosslinking experiments in Jurkat cells and probed eIF3 function to investigate miRNA-mediated translational regulation during T cell activation. We found that eIF3 interacts with multiple mature miRNAs in activated Jurkat cells, including members of the miR-17[~]92 cluster. These interactions also occur in primary T cells, as shown by RNA immunoprecipitation followed by qPCR (RIP-qPCR). Knocking out the miR-17[~]92 cluster led to a delay in ILR2A (CD25) cell surface expression in Jurkat cells and reduced activation-associated cell size increase in primary T cells during early T cell activation. In parallel, we used mass spectrometry to identify eIF3-interacting factors in activated primary T cells, and surprisingly found no evidence of Argonaute binding. Together, these findings provide evidence that eIF3-miRNA interactions may play an unappreciated role in translational control during early T cell activation.

Alzheimers Disease (AD) is the leading cause of dementia worldwide. Expression of the E4 variant of apolipoprotein E (APOE) greatly increases individuals risk of developing AD. In response to lipogenesis in astrocytes, APOE can escape secretion and traffic to the cytoplasmic surface of lipid droplets (LDs), but protein interactors of APOE at the LD were unknown. Here we find that LD-localized APOE physically interacts with the inflammatory lipid signaling enzyme cyclooxygenase-2 (COX-2). Like APOE, COX-2 can avoid the secretory pathway and traffic to LDs in response to lipogenesis. APOE3, but not APOE4, increases COX-2 localization to LDs. Computational modeling, microscopy-based assays, and targeted lipidomics reveal that APOE3 promotes while APOE4 suppresses COX-2 enzymatic activity at LDs and intracellular prostaglandin production. This work identifies a novel and targetable protein-protein interaction of APOE and provides a mechanistic link between APOE4 and dysregulated inflammatory lipid signaling.

CCCTC-binding factor (CTCF) is frequently mutated in endometrial cancer, resulting in genetic haploinsufficiency that contributes to tumour progression. We previously showed that depletion of CTCF disrupted cell polarity in KLE endometrial cancer spheroids; however, the implications for gene dysregulation and endometrial cancer pathophysiology remains poorly understood. ZNF185, an actin-associated and LIM domain-containing protein involved in cytoskeletal remodelling, was identified as a dysregulated target following CTCF haploinsufficiency. In this study, shRNA-mediated knockdown of CTCF was used to model haploinsufficiency in endometrial cancer cells, leading to the identification of a previously unrecognised isoform of ZNF185, named ZNF185B. Unlike the full-length protein, ZNF185B lacked co-localisation with F-actin and exhibited a diffuse cytoplasmic distribution, and ZNF185B was significantly upregulated in CTCF-depleted endometrial cancer cells and in an auxin-inducible degron model in a dose-dependent manner. Functional studies demonstrated that depletion of ZNF185 expression reduced endometrial cancer cell proliferation and clonogenic potential. Together, these findings identify ZNF185B as a novel isoform negatively regulated by CTCF protein dosage and establish ZNF185 as a requirement for endometrial cancer cell proliferation. Our results suggest that dysregulated ZNF185 expression is a crucial downstream consequence of CTCF haploinsufficiency and may contribute to tumour progression in endometrial cancer.

Human nucleoli are multivalent, involving contributions from up to ten NOR-bearing acrocentric chromosome p-arms. Precision mega-base scale chromosome engineering defines the requirements for this major genome organisational event. NOR deletions reveal that p-arm nucleolar association is rDNA independent. Deletion of all NOR-distal or proximal sequences individually have only a marginal effect on nucleolar association. Finally, deletion of an entire p-arm, while leaving centromere function intact, destroys the nucleolar association potential of that acrocentric. We propose that formation of multivalent nucleoli is not a nucleolar fusion event per se; rather it is driven by the surrounding chromosomal context of NORs.

Friedreich ataxia (FRDA) is a neurodegenerative and cardiac disease caused by GAA repeat expansions within the first intron of the FXN gene, leading to reduced frataxin expression. Frataxin is required for iron sulfur cluster (ISC) biosynthesis, and its deficiency results in multiple cellular dysfunctions, including mitochondrial iron overload. Although altered iron homeostasis has been reported in several frataxin-deficient models and in FRDA patients, its contribution to disease progression remains debated. Here, we used a GAA expansion-based Drosophila model of FRDA, termed fh-GAAs, to investigate the impact of reducing intestinal iron absorption on disease progression. We first found that iron accumulation was tissue-specific and predominantly affected the central nervous system. Furthermore, glial cells were affected more severely than neurons, suggesting an increased vulnerability of glia to frataxin deficiency. Reducing intestinal iron uptake, either through treatment with bathophenanthroline disulfonic acid (BPS), an extracellular iron chelator, or by gut-specific silencing of the iron transporter Malvolio, nearly doubled fly survival. BPS treatment also improved sensitivity to dietary iron, enhanced locomotor performance, fully restored normal brain size, and prevented glial alterations. Altogether, our findings identify glial cells as early and preferential targets of frataxin deficiency in an iron-dependent manner and support the in vivo relevance of intestinal iron uptake as a potential modulator of disease severity in FRDA.

Cellular adaptation to nutrient fluctuation is a fundamental biological process, crucial to cell fate, function, and survival. The choice between aerobic glycolysis and oxidative phosphorylation does not merely satisfy energetic requirements but actively shapes the cellular stress responses. Here we report that during the complex metabolic programming of CD8+ T cells, glucose utilization pathways correlate with the speed and nature of the response to glucose withdrawal. By quantitating systematic RNA-protein interactions in response to glucose withdrawal, we found that effector T cells mount acute transcriptional and post-transcriptional responses to the stress, while memory T cells exhibit slower, more limited responses. The functional dichotomy observed in T cells - between highly glycolytic cytotoxic effector cells and respiratory memory cells - exemplifies how distinct glucose utilization pathways impact immunological fate and function. Understanding the intricate interplay between metabolic modality, glucose pathways, and post-transcriptional control is crucial for deciphering environment adaptations and developing interventions in contexts ranging from immunotherapy to cancer biology.