Laboratoire de Spectrométrie de Masse Protéomique (LSMP)


Année de publication : 2018

Laencina Laura, Dubois Violaine, Le Moigne Vincent , Viljoen Albertus, Majlessi Laleh, Pritchard Justin, Bernut Audrey, Piel Laura, Roux Anne-Laure, Gaillard Jean-Louis, Lombard Bérengère, Loew Damarys, Rubin Eric J., Brosch Roland, Kremer Laurent, Herrmann Jean-Louis and Girard-Misguich Fabienne (2018 Jan 17)

Identification of genes required for Mycobacterium abscessus growth in vivo with a prominent role of the ESX-4 locus

Proceedings of the National Academy of Sciences of the United States of America : 115 : E1002-E1011 : DOI : 10.1073/pnas.1713195115 En savoir plus

The coevolution of mycobacteria and amoebae seems to have contributed to shaping the virulence of nontuberculous mycobacteria in macrophages. We identified a pool of genes essential for the intracellular survival of Mycobacterium abscessus inside amoebae and macrophages and discovered a hot spot of transposon insertions within the orthologous ESX-4 T7SS locus. We generated a mutant with the deletion of a structural key ESX component, EccB4. We demonstrate rupture of the phagosomal membrane only in the presence of an intact eccB4 gene. These results suggest an unanticipated role of ESX-4 T7SS in governing the intracellular behavior of a mycobacterium. Because M. abscessus lacks ESX-1, it is tempting to speculate that ESX-4 operates as a surrogate for ESX-1 in M. tuberculosis.


Année de publication : 2017

Sara Bizzotto, Ana Uzquiano, Florent Dingli, Dmitry Ershov, Anne Houllier, Guillaume Arras, Mark Richards, Damarys Loew, Nicolas Minc, Alexandre Croquelois, Anne Houdusse, Fiona Francis (2017 Dec 13)

Eml1 loss impairs apical progenitor spindle length and soma shape in the developing cerebral cortex.

Scientific reports : 17308 : DOI : 10.1038/s41598-017-15253-4 En savoir plus

The ventricular zone (VZ) of the developing cerebral cortex is a pseudostratified epithelium that contains progenitors undergoing precisely regulated divisions at its most apical side, the ventricular lining (VL). Mitotic perturbations can contribute to pathological mechanisms leading to cortical malformations. The HeCo mutant mouse exhibits subcortical band heterotopia (SBH), likely to be initiated by progenitor delamination from the VZ early during corticogenesis. The causes for this are however, currently unknown. Eml1, a microtubule (MT)-associated protein of the EMAP family, is impaired in these mice. We first show that MT dynamics are perturbed in mutant progenitor cells in vitro. These may influence interphase and mitotic MT mechanisms and indeed, centrosome and primary cilia were altered and spindles were found to be abnormally long in HeCo progenitors. Consistently, MT and spindle length regulators were identified in EML1 pulldowns from embryonic brain extracts. Finally, we found that mitotic cell shape is also abnormal in the mutant VZ. These previously unidentified VZ characteristics suggest altered cell constraints which may contribute to cell delamination.

Lucie Hebert, Dorine Bellanger, Chloé Guillas, Antoine Campagne, Florent Dingli, Damarys Loew, Alice Fievet, Virginie Jacquemin, Tatiana Popova, Didier Jean, Fatima Mechta-Grigoriou, Raphaël Margueron, Marc-Henri Stern (2017 Oct 27)

Modulating BAP1 expression affects ROS homeostasis, cell motility and mitochondrial function.

Oncotarget : 72513-72527 : DOI : 10.18632/oncotarget.19872 En savoir plus

The tumor suppressor BAP1 associates with ASXL1/2 to form the core Polycomb complex PR-DUB, which catalyzes the removal of mono-ubiquitin from several substrates including histone H2A. This complex also mediates the poly-deubiquitination of HCFC1, OGT and PCG1-α, preventing them from proteasomal degradation. Surprisingly, considering its role in a Polycomb complex, no transcriptional signature was consistently found among BAP1-inactivated tumor types. It was hypothesized that BAP1 tumor suppressor activity could reside, at least in part, in stabilizing proteins through its poly-deubiquitinase activity. Quantitative mass spectrometry and gene expression arrays were used to investigate the consequences of BAP1 expression modulation in the NCI-H226 mesothelioma cell line. Analysis of differentially expressed proteins revealed enrichment in cytoskeleton organization, mitochondrial activity and ROS management, while gene expression analysis revealed enrichment in the epithelial-to-mesenchymal transition pathway. Functional assessments in BAP1 inactivated, BAP1 wild-type and BAP1 catalytically dead-expressing NCI-H226 and QR mesothelioma cell lines confirmed alteration of these pathways and demonstrated that BAP1 deubiquitinase activity was mandatory to maintain these phenotypes. Interestingly, monitoring intracellular ROS levels partly restored the morphology and the mitochondrial activity. Finally, the study suggests new tumorigenic and cellular functions of BAP1 and shows for the first time the interest of studying the proteome as readout of BAP1 inactivation.

Alexandros Glentis, Philipp Oertle, Pascale Mariani, Aleksandra Chikina, Fatima El Marjou, Youmna Attieh, Francois Zaccarini, Marick Lae, Damarys Loew, Florent Dingli, Philemon Sirven, Marie Schoumacher, Basile G Gurchenkov, Marija Plodinec, Danijela Matic Vignjevic (2017 Oct 15)

Cancer-associated fibroblasts induce metalloprotease-independent cancer cell invasion of the basement membrane.

Nature communications : 924 : DOI : 10.1038/s41467-017-00985-8 En savoir plus

At the stage of carcinoma in situ, the basement membrane (BM) segregates tumor cells from the stroma. This barrier must be breached to allow dissemination of the tumor cells to adjacent tissues. Cancer cells can perforate the BM using proteolysis; however, whether stromal cells play a role in this process remains unknown. Here we show that an abundant stromal cell population, cancer-associated fibroblasts (CAFs), promote cancer cell invasion through the BM. CAFs facilitate the breaching of the BM in a matrix metalloproteinase-independent manner. Instead, CAFs pull, stretch, and soften the BM leading to the formation of gaps through which cancer cells can migrate. By exerting contractile forces, CAFs alter the organization and the physical properties of the BM, making it permissive for cancer cell invasion. Blocking the ability of stromal cells to exert mechanical forces on the BM could therefore represent a new therapeutic strategy against aggressive tumors.Stromal cells play various roles in tumor establishment and metastasis. Here the authors, using an ex-vivo model, show that cancer-associated fibroblasts facilitate colon cancer cells invasion in a matrix metalloproteinase-independent manner, likely by pulling and stretching the basement membrane to form gaps.