Biology subjects

Dibus, M.

Publications and source records attributed to Dibus, M..

5 recordsLinked to original sources

bioRxiv2025

Filopodome proteomics identifies CCT8 as a MYO10 interactor critical for filopodia functions

Cancer cells utilize filopodia to explore, adhere to, and invade their surrounding microenvironment, yet the protein networks that organize these protrusions remain incompletely defined. To uncover the molecular machinery underlying MYO10-positive filopodia, we targeted the fast biotin ligase TurboID to the filopo-dia tip-localized motor protein MYO10. Proximity biotinylation in two cell types revealed hundreds of potential MYO10 interactors. Surprisingly, there was limited overlap between the cell lines, indicating a previously unknown level of cell-type specificity in filopodia composition. A targeted microscopy and siRNA screen identified MINK1, SCRIB, CSNK1A1, and CCT8 as new regulators of filopodia formation. Focusing on one common interactor between cell lines, CCT8, known as a subunit of the chaperonin TRiC (TCP1 Ring Complex), we found that CCT8 associates with the MYO10 motor domain and regulates MYO10 filopodia independently of TRiC. Depleting CCT8 affected filopodia dynamics and impaired cell spreading, migration, and invasion in breast cancer cells. These findings establish CCT8 as a TRiC-independent regulator of MYO10 filopodia across different cancer cell types, highlight the surprising cell-type-specificity of filopodia composition, and provide a strategy and resource for studying filopodia in various biological contexts.

cell biology↗

bioRxiv2025

Adhesion-derived condensates control component availability to regulate adhesion dynamics

Integrin adhesion complexes mediate cell-extracellular matrix (ECM) interactions and undergo dynamic remodelling to regulate cell adhesion and migration. Here, we demonstrate that tensin 1 (TNS1), a multidomain adhesion adaptor protein linking active integrins with the actin cytoskeleton, undergoes phase separation in cells. Endogenous TNS1 condensates are formed upon focal adhesion disassembly or limited integrin-ECM engagement in both 2D and 3D environments, acting as reservoirs for inactive adhesion proteins. Combining functional experimental approaches with phosphoproteomics, we identify the TNS1 intrinsically disordered region as the main driver of TNS1 condensation and demonstrate a negative regulatory role of phosphorylation on condensate assembly upon activation of stress-responsive kinases. Finally, we confirm the functional effects of phosphorylation-dependent TNS1 condensation on adhesion dynamics and cell migration. Together, our findings highlight TNS1 condensation as a regulatory mechanism controlling local availability of inactive adhesion proteins, with direct implications on adhesion dynamics and cell behaviour.

cell biology↗

bioRxiv2024

Fast label-free live imaging reveals key roles of flow dynamics and CD44-HA interaction in cancer cell arrest on endothelial monolayers

Leukocyte extravasation is a key component of the innate immune response, while circulating tumor cell extravasation is a critical step in metastasis formation. Despite their importance, the mechanisms underlying leukocyte and tumor cell extravasation remain incompletely understood. Here, we developed an imaging pipeline that integrates fast, label-free live-cell imaging with deep learning-based image analysis to quantitatively track and compare the initial steps of extravasation--cell landing and arrest on an endothelial monolayer--under physiological flow conditions. We find that pancreatic ductal adenocarcinoma (PDAC) cells exhibit variable adhesion strength and flow sensitivity. Remarkably, some PDAC cells demonstrate comparable endothelial engagement as leukocytes, preferentially arresting at endothelial junctions, potentially due to increased stiffness at these sites, which leads to exposure to the underlying basal extracellular matrix. PDAC cells also tend to cluster in regions with high, heterogeneous expression of the endothelial CD44 receptor. Simulations suggest that clustering results from the combination of CD44-mediated attachment and localized flow disturbances that facilitate subsequent cell attachment. Targeting CD44 using siRNA or function-blocking antibodies, or degrading its ligand hyaluronic acid (HA), almost completely abolishes PDAC cell attachment. Overall, we demonstrate that cancer and immune cells share both common and unique features in endothelial adhesion under flow, and identify CD44 and HA as key mediators of PDAC cell arrest.

cell biology↗

bioRxiv2024

EPLINα controls integrin recycling from Rab21 endosomes to drive breast cancer cell migration

EPLIN, an actin-binding protein, has been described as both a tumour promoter and tumour suppressor in different cancers. EPLIN isoform( or {beta})-specific functions, which remain largely unknown, could explain these opposing roles. We observed distinct EPLIN-isoform localization; EPLIN is recruited to actin in plasma membrane ruffles and endosomes, while EPLIN{beta} resides on actin stress fibers. We identified two EPLIN actin-binding regions and demonstrated EPLIN interaction with Rab21, an established regulator of {beta}1-integrin endosomal traffic. EPLIN co-localizes with Rab21 and F-actin on recycling endosomes in an actin binding-dependent manner and supports {beta}1-integrin recycling and cell migration. Using BioID, we identified coronin 1C as an EPLIN proximal protein, which localizes at Rab21-containing endosomes in an EPLIN-dependent manner. EPLIN expression was linked to increased breast cancer cell motility, and high EPLIN-to-EPLIN{beta} ratio correlated with a mesenchymal phenotype in patient samples. Our work unveils unprecedented EPLIN isoform-specific functions relevant to breast cancer and beyond.

cell biology↗

bioRxiv2018

The interaction of p130Cas with PKN3 promotes malignant growth

Protein p130Cas constitutes an adaptor protein mainly involved in integrin signaling downstream of Src kinase. Owing to its modular structure, p130Cas acts as a general regulator of cancer cell growth and invasiveness induced by different oncogenes. However, other mechanisms of p130Cas signaling leading to malignant progression are poorly understood. Here, we show a novel interaction of p130Cas with Ser/Thr kinase PKN3, which is implicated in prostate and breast cancer growth downstream of phosphoinositide 3-kinase. This direct interaction is mediated by the p130Cas SH3 domain and the centrally located PKN3 polyproline sequence. PKN3 is the first identified Ser/Thr kinase to bind and phosphorylate p130Cas and to colocalize with p130Cas in cell structures that have a pro-invasive function. Moreover, the PKN3-p130Cas interaction is important for mouse embryonic fibroblast growth and invasiveness independent of Src transformation, indicating a distinct mechanism from that previously characterized for p130Cas. Together, our results suggest that the PKN3-p130Cas complex may represent an attractive therapeutic target in late-stage malignancies.\n\nSummaryGemperle et al. present the first report of an interaction between p130Cas with the serine/threonine kinase PKN3, implicated in prostate and breast cancer growth. They show that p130Cas colocalizes with PKN3 in cell structures that have a pro-invasive function and enhance our understanding of PKN3-mediated signaling and tumor growth.

cancer biology↗