Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2025.03.31.646258

The molecular and cellular interplay between the osteopetrosis-associated proteins SNX10, OSTM1, and CLC-7 during osteoclastogenesis

Reuven, N.·Winograd-Katz, S. E.·Barnea-Zohar, M.·Pri-Or, A.·Levin, Y.·Vacher, J.·Geiger, B.·Elson, A.
View original source ↗Export metadata ↓

Abstract

Bone-resorbing osteoclasts (OCLs) are large, multi-nucleated cells that are formed through well-regulated differentiation and cell fusion of monocyte-macrophage precursors. Disruption of OCL-mediated bone resorption perturbs bone formation, remodeling, and homeostasis that, in turn, can lead to severe illnesses, such as autosomal recessive osteopetrosis (ARO). Mutations in the intracellular trafficking-associated protein sorting nexin 10 (SNX10) lead to "OCL-rich" ARO, in which OCLs are produced but are inactive. Furthermore, OCL fusion is deregulated in SNX10-knockout (SKO) mice: mature mutant OCLs fuse continuously to generate gigantic cells, in vitro and in vivo, unlike wild-type OCLs that stop fusing with each other upon maturation. Mutations in CLC-7, the lysosomal voltage-gated Cl-/H+ exchanger, and OSTM1, the beta-chain of the exchanger, also induce ARO in humans and in mouse models, and are associated with the presence of large OCLs. This study explored the molecular interplay between SNX10, CLC-7 and OSTM1 by directly comparing the phenotypes of cultured OCLs lacking one of these proteins. We show that loss of SNX10, OSTM1, or CLC-7 leads to the formation of similarly-gigantic OCLs in culture, due to deregulated fusion between mature OCLs that proceeds with similar kinetics. All three proteins are associated with LAMP1-positive lysosomes, localized in both perinuclear and peripheral regions of mature wild-type OCLs. Co-immunoprecipitation studies indicated that SNX10 physically interacts with CLC-7. Notably, SNX10-KO OCLs exhibited a significant reduction in peripheral lysosomes containing CLC-7 and OSTM1, suggesting that SNX10 is required for their transport to the cell periphery. Taken together, these findings indicate that SNX10 regulates the subcellular distribution of lysosomes containing CLC-7 and OSTM1, thereby controlling both the fusion and functionality of mature OCLs.

Explore related subjects

cell biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Reuven, N., Winograd-Katz, S. E., Barnea-Zohar, M., Pri-Or, A., Levin, Y., Vacher, J., Geiger, B., Elson, A.. 2025-03-31. The molecular and cellular interplay between the osteopetrosis-associated proteins SNX10, OSTM1, and CLC-7 during osteoclastogenesis. https://doi.org/10.1101/2025.03.31.646258

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Not all TOP RNAs are created equal: 3'UTR length and TSS selection predict the translational regulation of LARP1-bound mRNAs in CD4+ T cells

Naive T cells are poised for activation and contain a pool of translationally repressed ribosomal protein (RP) mRNA prepared to induce ribosome biogenesis to support protein synthesis, cell growth and proliferation. RP mRNA are the prototypical members of a class of transcripts initiating at cytosine followed by a CU rich element called terminal oligo pyrimidine (TOP) RNAs. TOP RNAs are regulated by an RNA binding protein LARP1, which promotes transcript stabilisation and translational repression. We investigated LARP1 function in T cell activation by generating cross-linking immunoprecipitation (CLIP) datasets detailing the LARP1-RNA interactions in naive and activated CD4+ T cells and identifying novel TOP RNAs. TOP RNAs identified by this analysis were functionally diverse. RP mRNAs were typified by high stability, and translational repression in naive T cells followed by MTORC1-dependent translation increases following T cell activation. However, other TOP RNAs varied in these aspects of their regulation. Notably, TOP RNAs with longer 3'UTRs had a relaxed dependency on LARP1 for stability and a reduced dependency on MTORC1 for their translation. Transcription start site heterogeneity also impacted TOP RNA regulation by generating a mixture of transcript isoforms with different TOP motif lengths. Longer terminal oligo pyrimidine stretches were associated with a greater dependency on MTORC1 for translation. Differential regulation of TOP RNAs may allow tuneable translational responses to MTORC1 and indicates potential roles for LARP1 beyond translation regulation and stability.

cell biology↗
bioRxiv2026

Sex-specific metabolic regulation by the Drosophila RNA-binding protein Nab2

Conserved RNA binding proteins (RBPs) regulate key steps of gene expression including mRNA processing, export, localization, stability and translation. Human ZC3H14 is a conserved RBP that regulates pre-mRNA processing in neurons and loss of ZC3H14 leads to neurological defects. Studies of Nab2, the Drosophila orthologue of ZC3H14, have identified potential target RNAs involved in metabolism, suggesting Nab2 may influence neurometabolic circuitry. Here, we show a female-specific increase in dilp2 and dilp5 mRNA levels. The dilps encode insulin-like peptides that signal from the brain insulin producing cells (IPCs) to peripheral tissues. Nab2null females have enlarged lipid droplets in the fat body, a tissue analogous to human adipose tissue and liver. Notably, neuronal depletion of Nab2 increases lipid droplet size while neuronal expression of Nab2 in Nab2null female rescues this phenotype supporting a role for Nab2 in a neuronal circuit that regulates dilp levels. Furthermore, depletion of dilp2 or dilp5 from IPCs rescues the enlarged lipid droplet phenotype in Nab2null females indicating that elevated dilp2/dilp5 contributes to enlarged lipid droplets. Together, these data support a female-specific role for Nab2 in brain neurons to support insulin signaling and fat storage, expanding the known functions of RBPs linking neuronal function and metabolic homeostasis.

cell biology↗
bioRxiv2026

Deep generative embeddings of gene expression and splicing reposition the interpretation of single-cell transcriptomic signatures

Single-cell transcriptomic analysis predominantly derives cell identity from gene expression analysis, while alternative splicing is processed separately despite its fundamental role for cell homeostasis. To overcome the limits of separate investigations, we developed a probabilistic deep learning framework, Crecerelle, enabling resolution of the contributions of gene expression and alternative splicing in each cell. Crecerelle learns cell embeddings from gene expressions and alternative splicing isoforms, to decipher their mutually dependent impact on the functional characterisation of cells in a data-driven manner, exemplified for the Tabula Muris dataset. This is enabled through a zero-and-N-inflated Dirichlet-Multinomial for a variational autoencoder that learns cell embeddings solely from splicing profiles, as well as a bi-modal variational autoencoder with a relevance-weighted mixture-of-experts variational posterior to consolidate the modality-specific contribution at single-cell level. Crecerelle reveals cell-type-specific isoform markers as well as subpopulations with unique isoforms and uncovers regulatory and disease-associated pathways not detected by gene expression analyses alone. This scalable and interpretable framework thus allows a more holistic study of transcriptomic regulation and will open a route to modality-relevance-weighted investigations across single-cell multiomics datasets and their influence on cellular homeostasis, tissue development and disease phenotypes.

cell biology↗