Biology subjects

Carisey, A.

Publications and source records attributed to Carisey, A..

6 recordsLinked to original sources

bioRxiv2025

ER-to-Golgi Trafficking is a Nutrient-Sensitive Checkpoint Linking Glucose Starvation to Cell Surface Remodeling

Cancer cells adapt to nutrient stress by remodeling the repertoire of proteins on their surface, enabling survival and progression under starvation conditions. However, the molecular mechanisms by which nutrient cues reshape the cell surface proteome to influence cell behavior remain largely unresolved. Here, we show that acute glucose starvation, but not amino acid deprivation or mTOR inhibition, selectively impairs ER-to-Golgi export of specific cargoes, such as E-cadherin, in a SEC24C-dependent manner. Quantitative cell surface proteomics reveal that glucose deprivation remodels the cell surface proteome, notably reducing surface expression of key adhesion molecules. This nutrient-sensitive reprogramming enhances cell migration in vitro and promotes metastasis in vivo. Mechanistically, we show that AMPK and ULK1 signaling orchestrate this process independent of autophagy, with ULK1-mediated phosphorylation of SEC31A driving SEC24C-dependent COPII reorganization. These findings establish ER-to-Golgi trafficking as a nutrient-sensitive regulatory node that links metabolic stress to cell surface remodeling and metastatic potential.

cell biology↗

bioRxiv2024

MAGE-A4-Responsive Plasma Cells Promote Non-Small Cell Lung Cancer

Adaptive immunity is critical to eliminate malignant cells, while multiple tumor-intrinsic factors can alter this protective function. Melanoma antigen-A4 (MAGE-A4), a cancer-testis antigen, is expressed in several solid tumors and correlates with poor survival in non-small cell lung cancer (NSCLC), but its role in altering antitumor immunity remains unclear. We found that expression of MAGE-A4 was highly associated with the loss of PTEN, a tumor suppressor, in human NSCLC. Here we show that constitutive expression of human MAGE-A4 combined with the loss of Pten in mouse airway epithelial cells results in metastatic adenocarcinoma enriched in CD138+ CXCR4+ plasma cells, predominantly expressing IgA. Consistently, human NSCLC expressing MAGE-A4 showed increased CD138+ IgA+ plasma cell density surrounding tumors. The abrogation of MAGE-A4-responsive plasma cells (MARPs) decreased tumor burden, increased T cell infiltration and activation, and reduced CD163+CD206+ macrophages in mouse lungs. These findings suggest MAGE-A4 promotes NSCLC tumorigenesis, in part, through the recruitment and retention of IgA+ MARPs in the lungs.

immunology↗

bioRxiv2023

A fluorogenic complementation tool kit for interrogating lipid droplet-organelle interaction

Contact sites between lipid droplets and other organelles are essential for cellular lipid and energy homeostasis. Detection of these contact sites at nanometer scale over time in living cells is challenging. Here, we developed a tool kit for detecting contact sites based on Fluorogen- Activated Bimolecular complementation at CONtact sites, FABCON, using a reversible, low affinity split fluorescent protein, splitFAST. FABCON labels contact sites with minimal perturbation to organelle interaction. Via FABCON, we quantitatively demonstrated that endoplasmic reticulum (ER)- and mitochondria (mito)-lipid droplet contact sites are dynamic foci in distinct metabolic conditions, such as during lipid droplet biogenesis and consumption. An automated analysis pipeline further classified individual contact sites into distinct subgroups based on size, likely reflecting differential regulation and function. Moreover, FABCON is generalizable to visualize a repertoire of organelle contact sites including ER-mito. Altogether, FABCON reveals insights into the dynamic regulation of lipid droplet-organelle contact sites and generates new hypotheses for further mechanistical interrogation during metabolic switch.

cell biology↗

bioRxiv2022

The efficiency of p27 peptide cleavage during in vitro respiratory syncytial virus (RSV) infection is cell line and RSV subtype dependent

Respiratory Syncytial Virus (RSV) Fusion protein (F) is highly conserved between RSV/A and RSV/B subtypes. To become fully active, F precursor undergoes enzymatic cleavage to yield F1 and F2 subunits and releases a 27 amino acid peptide (p27). Virus-cell fusion occurs when RSV F undergoes a conformational change from pre-F to post-F. Previous immunological and cell-surface expression data show that p27 is detected on RSV F, but questions remain on how p27 effects the conformation of mature RSV F. Monoclonal antibodies against p27, Site O (pre-Fusion specific), and Site II were used to monitor RSV F conformation by ELISA and Imaging Flow Cytometry. Pre-F to post-F conformational change was induced by temperature-stress test. We found that p27 cleavage efficiency was lower on sucrose purified (sp) RSV/A than on spRSV/B. In addition, in vitro cleavage of RSV F was cell-line dependent, higher levels of p27 expression were observed on surface of RSV infected HEp-2 cells than A549 cells. Higher levels of p27 were also found on RSV/A infected cells compared to RSV/B. We observed that RSV/A F with higher levels of p27 could better sustain the pre-F conformation during the temperature-stress challenge in both spRSV and as well RSV-infected cell lines. Our findings suggest that despite F sequence similarity, the p27 of RSV subtypes is cleaved with different efficiencies, which were also dependent on the cell lines used for infection. We therefore speculate that partially cleaved p27 may confer higher stability to the pre-F and provides a fitness advantage. IMPORTANCEThe RSV fusion protein (F) plays an important role in entry and viral fusion to the host cell. The F protein undergoes proteolytic cleavages by furin protease resulting in the release of a 27 amino acid peptide (p27) to become fully functional. During this process, the F protein also undergoes a conformational change from metastable pre-F to highly stable post-F. For decades, the consensus in the RSV field was that p27 was not present in the fully mature RSV F protein. Therefore, the role of the p27 peptide in viral entry and the function of the partially cleaved F protein containing p27 has been overlooked. However, recent developments have shown that p27 elicits an immune response during natural infection and that p27 can be found in vitro and in animal models infected with the prototypical RSV/A strain. In this study, we were able to detect p27 on purified RSV virions and on the surface of virus-infected cells of two widely used cell lines, HEp-2 and A549 cells for both prototypical and contemporary circulating RSV strains of both subtypes. Also, higher levels of partially cleaved F protein containing p27 could better sustain the pre-F conformation during the temperature-stress challenge. Our findings highlight that the cleavage efficiency of p27 is different between RSV subtypes and among cell lines and that the presence of p27 in partially cleaved F protein likely contributes to the stability of the pre-F conformation.

microbiology↗

bioRxiv2019

Force-independent interactions of talin and vinculin govern integrin-mediated mechanotransduction

Talin, vinculin and paxillin are core components of the dynamic link between integrins and actomyosin. Here we study the mechanisms that mediate their activation and association using a mitochondrial-targeting assay, structure-based mutants, and advanced microscopy. As expected, full-length vinculin and talin are auto-inhibited and do not interact with each other in this state. Contrary to previous models that propose a critical role for forces driving talin-vinculin association, our data show that force-independent relief of auto-inhibition is sufficient to mediate their tight interaction. Interestingly, paxillin can bind to both talin and vinculin when either is inactive. Further experiments demonstrate that adhesions containing paxillin and vinculin can form without talin following integrin activation. However, these are largely deficient in exerting traction forces to the matrix. Our observations lead to a model whereby paxillin contributes to talin and vinculin recruitment into nascent adhesions. Activation of the talin-vinculin axis subsequently leads to the engagement with the traction force-machinery and focal adhesion maturation.

cell biology↗

bioRxiv2017

FiloQuant reveals increased filopodia density during DCIS progression

Filopodia are commonly observed cellular protrusions in vitro and in vivo. Defective filopodia formation is linked to several pathologies including cancer, wherein actively protruding filopodia, at the invasive front, and filopodia-mediated probing of the microenvironment accompanies cancer cell dissemination. Despite wide biological significance, delineating the function of these finger-like protrusions in more complex systems remains technically challenging, particularly hindered by lack of compatible methods to quantify filopodia properties. Here, we present FiloQuant, a freely available ImageJ plugin, to detect filopodia and filopodia-like protrusions in both fixed and live-cell microscopy data. We demonstrate that FiloQuant can extract quantifiable information including protrusion dynamics, density and length from multiple cell types and in a range of microenvironments, such as during collective or single cancer cell migration in 2D and 3D, in fixed neuronal cultures, in activated natural killer cells and in sprouting endothelial cells in vivo. In cellular models of breast ductal carcinoma in situ (DCIS) we reveal a link between filopodia formation at the cell-matrix interface, during collective invasion and in 3D tumour spheroids, with the previously reported local invasive potential of these breast cancer models in vivo. Finally, using intravital microscopy, we observed that tumour spheroids display prominent filopodia in vivo, supporting a potential role for these protrusions during tumorigenesis.

cell biology↗