Biology subjects

Gautier, E.-F.

Publications and source records attributed to Gautier, E.-F..

4 recordsLinked to original sources

bioRxiv2025

The protein-protein interaction landscape of Fanconi anemia protein A (FANCA) reveals its contributions to mRNA processes.

Fanconi Anemia (FA) is a rare inherited recessive disorder characterized by bone marrow failure, congenital abnormalities, and a predisposition to myeloid leukemia and some solid cancers. FA is caused by mutations in one of the 22 so-called FANC genes, with two thirds of FA patients being FANCA mutants. FANC proteins cooperate within the FANC/BRCA pathway, a DNA repair system essential for resolving DNA interstrand crosslinks (ICLs) in S-phase. The canonical understanding of FA pathogenesis involves genome instability and impaired cellular proliferation due to DNA damage accumulation and stress response overactivation. However, recent data shows FANCA has a function in ribosome biogenesis and translation, which prompts a reassessment of FANCAs role(s) in cellular physiology and FA pathogenesis. We reasoned that unveiling the multiple interactions of the FANCA protein would shed light on these potentially new FANCA functions. By combining immunoprecipitation and BioID approaches, in three different cell lines and with different in silico analysis methods, we constructed lists of FANCA interactome proteins of different levels of selectivity and assembled them into a novel multilayered FANCA protein-protein interaction (PPI) landscape. Strikingly, we find that FANCA associates with proteins involved in processes distinct from DNA repair, such as translation, ribosome biogenesis, mRNA splicing, nucleocytoplasmic transport, chromatin remodeling, and the TCA cycle. We then analyzed the protein content of polysome profiling fractions and found that FANCA loss may affect ribosomal protein stoichiometry within ribosomal subunits. Overall, our data expands FANCAs PPI network far beyond the previously reported interactions. Importantly, we confirm the biological significance of low-selectivity interactions and propose to re-evaluate their importance in proteomic studies. The study of previously unsuspected FANCA functions, such as translation, could provide new therapeutic targets in FA and therefore improve patient care.

genetics↗

bioRxiv2024

VEXAS anemia is a mosaic erythroblastopenia

VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) is a recently discovered autoinflammatory disorder linked to somatic mutations in the UBA1 gene, resulting in a profound cytoplasm-restricted defect in ubiquitylation. The disease is characterized by a macrocytic anemia that remains poorly understood. To investigate the erythroid lineage in VEXAS, we conducted a comprehensive study combining in vivo assessments of patients mature red cells and marrow erythroblasts, alongside in vitro base-editing models of erythropoiesis. Here we show that mature red cells do not exhibit ubiquitylation defects, and patient-derived bone marrow erythroblasts lack UBA1 mutations beyond the basophilic stage of erythroid differentiation. In vitro base editing of UBA1 variants in CD34+ primary cells resulted in high mortality during early erythroid differentiation, but not during monocytic differentiation. Edited erythroid precursors displayed TP53 overexpression linked to defective ubiquitylation and anomalies in ribosome biogenesis, reminiscent of Diamond-Blackfan anemia. We propose that VEXAS-associated anemia should be considered as a mosaic erythroblastopenia, where the severity of anemia is influenced by the quality and quantity of the UBA1-WT compartment. These insights may aid clinicians in tailoring treatment strategies.

cell biology↗

bioRxiv2024

Proteostasis and metabolic dysfunction in a distinct subset of storage-induced senescent erythrocytes targeted for clearance

Although refrigerated storage slows the metabolism of volunteer donor RBCs, cellular aging still occurs throughout this in vitro process, which is essential in transfusion medicine. Storage-induced microerythrocytes (SMEs) are morphologically-altered senescent RBCs that accumulate during storage and which are cleared from circulation following transfusion. However, the molecular and cellular alterations that trigger clearance of this RBC subset remain to be identified. Using a staining protocol that sorts long-stored SMEs (i.e., CFSEhigh) and morphologically-normal RBCs (CFSElow), these in vitro aged cells were characterized. Metabolomics analysis identified depletion of energy, lipid-repair, and antioxidant metabolites in CFSEhigh RBCs. By redox proteomics, irreversible protein oxidation primarily affected CFSEhigh RBCs. By proteomics, 96 proteins, mostly in the proteostasis family, had relocated to CFSEhigh RBC membranes. CFSEhigh RBCs exhibited decreased proteasome activity and deformability; increased phosphatidylserine exposure, osmotic fragility, and endothelial cell adherence; and were cleared from the circulation during human spleen ex vivo perfusion. Conversely, molecular, cellular, and circulatory properties of long-stored CFSElow RBCs resembled those of short-stored RBCs. CFSEhigh RBCs are morphologically and metabolically altered, have irreversibly oxidized and membrane-relocated proteins, and exhibit decreased proteasome activity. In vitro aging during storage selectively alters metabolism and proteostasis in SMEs, targeting these senescent cells for clearance.

cell biology↗

bioRxiv2018

Deep proteomic analysis of chicken erythropoiesis

In contrast to mammalian erythroid cells that lost their nucleus at the end of the differentiation process, circulating chicken erythrocytes, like erythrocytes of most other non-mammalian vertebrates, are nucleated although their nucleus is believed to be transcriptionally silent. This major difference suggests that the erythroid differentiation process is likely to present both similarities and differences in mammals compared to other vertebrates. Since proteins are the major cellular effectors, analysis of the proteome is more prone to reflect true differences than analysis of the pattern of mRNA expression. We have previously reported the evolution of the proteome of human erythroid cells throughout their differentiation process. Here we report the analysis of the proteome of chicken erythroblasts during their terminal differentiation. We used the T2EC cellular model that allows to obtain homogenous populations of immature erythroblasts. Induction of their terminal differentiation led to their maturation and the possibility to obtain cells at different differentiation stages. Mass spectrometry analysis of these cell populations allowed the absolute quantification of 6167 proteins throughout the terminal differentiation process. Beside many proteins with similar expression patterns between chicken and human erythroblasts, like SLC4A1 (Band3), GATA1 or CD44, this analysis also revealed that other important proteins like Kit or other GATA transcription factors exhibit fully different patterns of expression.

developmental biology↗