Biology subjects

Blangy, A.

Publications and source records attributed to Blangy, A..

4 recordsLinked to original sources

bioRxiv2024

Src promotes tumor cell invasion by hijacking the translation machinery

The Src oncogene controls cancer cell invasiveness by promoting invadosome formation and extracellular matrix degradation (ECM). Invadosomes are enriched in the eukaryotic translation initiation factor 3 (eIF3) complex associated with a local mRNA translation activity mandatory for their maintenance. Here, we show that Src regulates mRNA translation by controlling the expression of eIF3 subunits. Among them, eIF3h/e/d are essential for invadosome formation and ECM degradation. We demonstrate that Src controls the canonical mTOR/eIF4E and the non-canonical eIF3d cap-dependent translation initiation pathways. We show that both pathways are necessary for invadosome formation and their ECM degradation function. Finally, we highlighted a correlation between Src and eIF3h/e/d overexpression, which is associated with poor prognosis in hepatocellular carcinoma (HCC) patients and controls the ECM degradation and invasive properties of HCC cells. These findings identify Src as a major regulator of translation initiation pathways, which leads to invadosome formation, ECM degradation and tumor cell invasion. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/606119v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@1804203org.highwire.dtl.DTLVardef@16ddae8org.highwire.dtl.DTLVardef@13ecca5org.highwire.dtl.DTLVardef@1ed685a_HPS_FORMAT_FIGEXP M_FIG Graphical abstract C_FIG

cell biology↗

bioRxiv2019

Dock5 is a new regulator of microtubule dynamic instability through GSK3β inhibition in osteoclasts

Background informationOsteoclast resorption is dependent on a podosome-rich structure, called sealing zone, which is stabilized by acetylated microtubules. It tightly attaches the osteoclast to the bone creating a favorable acidic microenvironment for bone degradation. We already established that Rac activation by Dock5 is necessary for osteoclast resorption. Indeed, inhibition of Dock5 in osteoclasts results in Rac1 decreased activity associated to impaired podosome assembly into sealing zones and resorbing activity.\n\nResultsIn this report, we show that Dock5 knockout osteoclasts also present a reduced acetylated tubulin level leading to a decreased length and duration of microtubule growth phases whereas their growth speed remains unaffected. Dock5 does not act by direct interaction with the polymerized tubulin but through inhibition of the microtubules destabilizing kinase GSK3{beta} downstream of Akt activation. Interestingly, we ruled out the implication of Rac1 in this process using specific inhibitors.\n\nConclusionOur data involve Dock5 as a new regulator of microtubule dynamic instability in osteoclast.\n\nSignificanceThe fact that Dock5 is a regulator of both actin cytoskeleton and microtubule dynamics makes it an interesting therapeutic target for osteolytic pathologies because of its dual role on sealing zone formation and stabilization.

cell biology↗

bioRxiv2019

The atypical Rho GTPase RhoU interacts with Intersectin-2 to regulate endosomal recycling pathways

Rho GTPases play a key role in various membrane trafficking processes. RhoU is an atypical small Rho GTPase related to Rac/Cdc42 which possesses unique N- and C-terminal domains that regulate its function and its subcellular localization. RhoU localized at the plasma membrane, on endosomes and in cell adhesion structures where it governs cell signalling, differentiation and migration. However, despite its endomembrane localization, RhoU function in vesicular trafficking has been unexplored. Here, we identified intersectins (ITSNs) as new binding partners for RhoU and showed that the second PxxP motif at the N-terminus of RhoU mediated interactions with SH3 domains of ITSNs. To evaluate the function of RhoU and ITSNs in vesicular trafficking, we used fluorescent transferrin as a cargo for uptake experiments. We showed that silencing of either RhoU or ITSN2, but not ITSN1 increased transferrin accumulation in early endosomes resulting from defect in fast vesicle recycling. Concomitantly, RhoU and ITSN2 colocalized to a subset of Rab4-positive vesicles suggesting that RhoU-ITSN2 interaction may occur on fast recycling endosomes to regulate the fate of vesicular cargos.

cell biology↗

bioRxiv2018

Combined strategy of siRNA and osteoclast actin cytoskeleton automated imaging to identify novel regulators of bone resorption shows a non-mitotic function for anillin.

Osteoclasts are the main cells responsible for the resorption of mineralized extracellular matrices. They are the major targets for anti-resorptive therapies to manage osteoporosis, a major public health problem. Osteoclasts are giant multinucleated cells that can organize their a unique adhesion structure based on a belt of podosomes, which is the keystone of the bone resorption apparatus. We combined differential transcriptomics and siRNA screening approaches to get a broader view of cytoskeletal regulators that participate in the control of osteoclast cytoskeleton and identify novel regulators of bone resorption by osteoclasts. We identified 20 new candidate regulators of osteoclasts cytoskeleton including Fkbp15, Spire1, Tacc2 and RalA, for which we confirmed they are necessary for proper organization of the podosome belt. We also showed that Anillin, well known for its role during cytokinesis, is essential in osteoclasts for correct podosome patterning and efficient bone resorption. In particular, Anillin controls the levels of the GTPase RhoA, a known regulator of osteoclast cytoskeleton and resorption activity. Finally, we set up and validated an automated imaging strategy based on open-source software for automatic and objective measurement of actin cytoskeleton organization in osteoclasts. We provide these pipelines that are useful to automatically assess the effect of collections of siRNAs or chemical compounds on osteoclast cytoskeleton or differentiation.

cell biology↗