Biology subjects

BLANGY, A.

Publications and source records attributed to BLANGY, A..

3 recordsLinked to original sources

bioRxiv2025

ARHGAP10 is a novel microtubule-associated protein that regulates the resorption activity of osteoclasts

Adult-bone homeostasis is maintained through the reciprocal actions of osteoclasts and osteoblasts, which respectively resorb and deposit new bone. Excessive osteoclast activity leads to bone loss and contributes to conditions like osteoporosis. Osteoclasts form a specialized adhesion structure called the actin ring that is crucial for bone resorption and relies on both the actin and microtubule cytoskeletons. Our previous studies identified the {beta}-tubulin isotype TUBB6 as a regulator of actin ring dynamics essential for osteoclast function, and found ARHGAP10, a negative regulator of the GTPases CDC42 and RHOA, as a potential mediator of TUBB6 function. Here we show that ARHGAP10 is a novel microtubule-associated protein critical for osteoclast function. ARHGAP10 directly binds microtubules through its BAR-PH domain, which requires positively-charged lysine residues K37, K41 and K44 within the BAR domain. CRISPR/Cas9 mediated knockout of Arhgap10 affects the morphology of the actin ring and impairs osteoclast resorption activity, correlated with altered actin ring dynamics. Complementation experiments reveal that the ability of ARHGAP10 to bind microtubules and to negatively regulate RHO-GTPases are essential for its role in osteoclast resorption activity. These findings uncover a novel cytoskeletal regulator in osteoclasts and suggest that targeting the microtubule-actin interface via ARHGAP10 could represent a therapeutic strategy in bone loss disorder.

cell biology↗

bioRxiv2021

The beta-tubulin isotype TUBB6 controls microtubule and actin dynamics in osteoclasts.

Osteoclasts are bone resorbing cells that participate in the maintenance of bone health. Pathological increase in osteoclast activity causes bone loss eventually resulting in osteoporosis. Actin cytoskeleton of osteoclasts organizes into a belt of podosomes, which sustains the bone resorption apparatus and is maintained by microtubules. Better understanding of the molecular mechanisms regulating osteoclast cytoskeleton is key to understand the mechanisms of bone resorption, in particular to propose new strategies against osteoporosis. We reported recently that {beta}-tubulin isotype TUBB6 is key for cytoskeleton organization in osteoclasts and for bone resorption. Here, using an osteoclast model CRISPR/Cas9 KO for Tubb6, we show that TUBB6 controls both microtubule and actin dynamics in osteoclasts. Osteoclasts KO for Tubb6 have reduced microtubule growth speed with longer growth life time, higher levels of acetylation and smaller EB1-caps. On the other hand, lack of TUBB6 increases podosome life time while the belt of podosomes is destabilized. Finally, we performed proteomic analyses of osteoclast microtubule-associated protein enriched fractions. This highlighted ARHGAP10 as a new microtubule-associated protein, which binding to microtubules appears to be negatively regulated by TUBB6. ARHGAP10 is a negative regulator of CDC42 activity, which participates in actin organization in osteoclasts. Our results suggest that TUBB6 plays a key role in the control of microtubule and actin cytoskeleton dynamics in osteoclasts. Moreover, by controlling ARHGAP10 association with microtubules, TUBB6 may participate in the local control CDC42 activity to ensure efficient bone resorption.

cell biology↗

bioRxiv2019

Quantitative proteomics and transcriptomics exploration of primary myeloid cells: importance of β tubulin isotypes for bone resorption.

Among hematopoietic cells. osteoclasts (Oc) and immature dendritic cells (Dc) are closely related myeloid cells with distinct functions; Oc participate skeleton maintenance while Dc sample the environment for foreign antigens. Such specificities rely on profound modifications of gene and protein expression during Oc and Dc differentiation. We provide global proteomic and transcriptomic analyses of primary mouse Oc and Dc. based on original SILAC and RNAseq data. We established specific signatures for Oc and Dc including genes and proteins of unknown functions. In particular. we showed that Oc and Dc have the same and {beta} tubulin isotypes repertoire but that Oc express much more {beta} tubulin isotype Tubb6. In both mouse and human Oc. we demonstrate that elevated expression of Tubb6 in Oc is necessary for correct podosomes organization and thus for the structure of the sealing zone. which sustains the bone resorption apparatus. Hence. lowering Tubb6 expression hindered Oc resorption activity. Overall. we highlight here potential new regulators of Oc and Dc biology and illustrate the functional importance of the tubulin isotype repertoire in the biology of differentiated cells. Summary statementThis study provides original proteomic and transcriptomic data of primary myeloid cells. The analysis led to signatures for osteoclasts and for immature dendritic cells including potential new regulators of their specific biology. RNA interference showed in particular that {beta} tubulin isotype Tubb6 participates in osteoclast podosome patterning. sealing zone structure and in the resorption activity.

cell biology↗