Biology subjects

Gigli, G.

Publications and source records attributed to Gigli, G..

5 recordsLinked to original sources

bioRxiv2026

Electrically programmable picoscale phototransduction of a newly discovered microbial rhodopsin

Human retina can achieve single-photon sensitivity through specialised photoreceptors that convert light into electrical signals via phototransduction. Among microbial light-sensitive proteins, proteorhodopsins stand out for their intrinsic light-driven ion transport and spectral tunability, making them promising candidates for bio-inspired photonic devices. A central challenge for acellular integration, however, is the fragility of most bacterial rhodopsins under extreme conditions. Here, we exploit the exceptional robustness of TARA76, a microbial rhodopsin that retains structural integrity even upon complete dehydration, to demonstrate its functional reconstitution in an artificial black lipid membrane within a biocompatible microfluidic platform. By recording light-induced ionic currents with picoampere sensitivity across a broad range of pH, illumination power, electrolyte composition, and applied voltages, we establish TARA76 as a high-performance photoelectric transducer in a fully acellular environment. Strikingly, we uncover a strong and previously unreported dependence of the photocurrent on Na+ ions, which appears to play a key structural and functional role in stabilising the proteins active conformation. Furthermore, we demonstrate that the orientation of TARA76 within the artificial membrane can be externally controlled by applying a defined electric field during bilayer formation, enabling deterministic tuning of photocurrent directionality. Together, these results establish a robust and miniaturisable bio-photonic platform with direct implications for quantum light sensing, neuromorphic bioelectronics, and next-generation artificial retinal interfaces.

biophysics↗

bioRxiv2026

Differential TIM-3 glycosylation enables specific dual targeting CAR-T therapy in acute myeloid leukemia

Chimeric Antigen Receptor (CAR) therapy for Acute Myeloid Leukemia (AML) is hindered by disease heterogeneity, antigen overlap with normal hematopoiesis, and the persistence of leukemic stem cells (LSCs). To overcome these barriers, we employed the IF-BETTER strategy to simultaneously target CD33 and the LSC-associated marker TIM-3 by pairing a second-generation CAR with a Cytokine-Costimulatory Receptor (CCR) in two dual CAR configurations (CD33.CAR/TIM-3.CCR and TIM-3.CAR/CD33.CCR). Both constructs displayed potent antigen-restricted cytotoxicity against AML cell lines and primary blasts, achieving leukemia clearance, while sparing normal immune and hematopoietic cells. Mechanistic studies revealed that the TIM-3.CAR single-chain fragment variable (scFv) recognizes a protein-proximal epitope whose interaction is selectively enhanced by AML-specific hyper-fucosylated and hyper-sialylated N-glycans. Fucosylation blockade reduced TIM-3.CAR avidity and cytotoxicity, confirming a glycosylation-modulated interaction. Integrating this glycosylation-tolerant TIM-3 scFv into a dual CAR framework enables selective targeting of AML cells, providing a rational strategy for safer and more effective AML-directed immunotherapy.

immunology↗

bioRxiv2025

TUSC3 serves as a rate-limiting gatekeeper of a glycan-mediated ER Triage Checkpoint for BMP4/Dpp

Trimming of the three glucose residues decorating nascent N-glycoproteins is a critical step for their entry into the endoplasmic reticulum quality control (ERQC) cycle and recognition by ER chaperones. However, the functional relevance of the second glucose (G2) and the regulatory step upstream of its removal by ER glucosidase II (GCS2) remains poorly understood. Here, we report that TUSC3, a component of the oligosaccharyltransferase (OST) complex, regulates G2 to G1 trimming on N-glycosylated bone morphogenetic protein 4 (BMP4) and its Drosophila homolog Dpp to promote their ERQC entry. Loss- and gain-of-function genetic experiments and biochemical assays in mammalian cells and flies indicate that TUSC3 serves as a dosage-sensitive gatekeeper that influences the decision between proper folding and secretion versus elimination by ER-associated degradation for BMP4 molecules, thereby tuning BMP signaling. Together, these data reveal an unrecognized role for an OST component in early glycoprotein maturation, relevant to a major developmental signaling pathway.

developmental biology↗

bioRxiv2025

Mechanical Cues Regulate Cargo Sorting and Export at the Golgi

The secretory pathway is a sophisticated endomembrane machinery designed to transport and deliver proteins and lipids to intracellular organelles and the extracellular space. While the molecular components of the secretory pathway are well understood, less is known about their regulation, especially by mechanical cues. Here, we report that substrate stiffness stimulates conventional secretion. We have unravelled a molecular pathway that links a mechanical cue through Src and FAK kinases to promote the trafficking of secretory proteins out of the Golgi apparatus and prevent their post-Golgi lysosomal degradation. Phosphoproteomic analysis revealed the Golgi-specific Brefeldin A resistance factor 1 (GBF1) as a key downstream mechano-responsive regulator, whose phosphorylation state orchestrates post-Golgi cargo sorting, directing proteins either toward secretion or to lysosomes. Finally, we identified AMPK as a stiffness-dependent upstream regulator of GBF1 phosphorylation. Together, our data reveal a molecular regulatory loop in which matrix stiffness positively regulates cellular secretion via the Src-FAK-AMPK-GBF1 axis, which can have relevant medical implications in conditions like cancer and fibrosis and their treatment.

cell biology↗

bioRxiv2022

Probing single cell fermentation flux and intercellular exchange networks via pH-microenvironment sensing and inverse modeling

The homeostatic control of their environment is an essential task of living cells. It has been hypothesized that when microenvironmental pH inhomogeneities are induced by high cellular metabolic activity, diffusing protons act as signaling molecules, driving the establishment of cross-feeding networks sustained by the cell-to-cell shuttling of overflow products such as lactate. Despite their fundamental role, the extent and dynamics of such networks is largely unknown due to the lack of methods in single cell flux analysis. In this study we provide direct experimental characterization of such exchange networks. We devise a method to quantify single cell fermentation fluxes over time by integrating high-resolution pH microenvironment sensing via ratiometric nanofibers with constraint-based inverse modeling. We apply our method to cell cultures with mixed populations of cancer cells and fibroblasts. We find that the proton trafficking underlying bulk acidification is strongly heterogeneous, with maximal single cell fluxes exceeding typical values by up to 3 orders of magnitude. In addition, a crossover in time from a networked phase sustained by densely connected "hubs" (corresponding to cells with high activity) to a sparse phase dominated by isolated dipolar motifs (i.e. by pair-wise cell-to-cell exchanges) is uncovered, which parallels the time course of bulk acidification. Our method promises to shed light on issues ranging from the homeostatic function of proton exchange to the metabolic coupling of cells with different energetic demands, and paves the way for real-time non-invasive single cell metabolic flux analysis.

biophysics↗