Biology subjects

Pardo-Pastor, C.

Publications and source records attributed to Pardo-Pastor, C..

4 recordsLinked to original sources

bioRxiv2026

Piezo1 balances focal and reticular adhesions to enable EGFR clathrin-mediated endocytosis

Cells attach to the extracellular matrix through distinct integrin-mediated adhesive structures, including force-transmitting focal adhesions (FAs) and clathrin-enriched reticular adhesions (RAs). FAs enable mesenchymal cell migration and disassemble at mitotic entry, whereas RAs impede migration, persist during mitosis, and contribute to clathrin-mediated endocytosis (CME) as they disassemble. FAs grow with RhoA contractility, whereas RAs shrink, but the mechanisms coordinating these opposing responses remain unclear. Here, we identify the mechanically activated ion channel Piezo1 as a master regulator of FA/RA balance. Piezo1-dependent calcium influx activates the Src family kinase Fyn, which activates two actin polymerization pathways: FA and stress fiber growth via VAV2-RhoA and RA disassembly via N-WASP-Arp2/3. Inhibition or knockdown of Piezo1, Fyn, or VAV2 decreases FA size and increases RA coverage. Critically, cells lacking Piezo1 fail to internalize ligand-activated EGFR on stiff substrates despite normal CME on soft substrates, establishing an essential role for Piezo1 in EGFR CME mechanoadaption. Our findings reveal Piezo1 as the mechanosensor linking membrane tension to coordinated actin polymerization pathways that co-regulate cell-matrix adhesion and endocytosis. Given that CME contributes to viral entry into host cells and cancer resistance to anti-EGFR antibody therapy, targeting the Piezo1-RA-CME axis may offer novel therapeutic opportunities.

cell biology↗

bioRxiv2023

Voltage-dependent volume regulation controls epithelial cell extrusion and morphology

Epithelial cells work collectively to provide a protective barrier, yet also turn over rapidly by cell death and division. If the number of dying cells does not match those dividing, the barrier would vanish, or tumors can form. Mechanical forces and the stretch-activated ion channel (SAC) Piezo1 link both processes; stretch promotes cell division and crowding triggers cell death by initiating live cell extrusion1,2. However, it was not clear how particular cells within a crowded region are selected for extrusion. Here, we show that individual cells transiently shrink via water loss before they extrude. Artificially inducing cell shrinkage by increasing extracellular osmolarity is sufficient to induce cell extrusion. Pre-extrusion cell shrinkage requires the voltage-gated potassium channels Kv1.1 and Kv1.2 and the chloride channel SWELL1, upstream of Piezo1. Activation of these voltage-gated channels requires the mechano-sensitive Epithelial Sodium Channel, ENaC, acting as the earliest crowd-sensing step. Imaging with a voltage dye indicated that epithelial cells lose membrane potential as they become crowded and smaller, yet those selected for extrusion are markedly more depolarized than their neighbours. Loss of any of these channels in crowded conditions causes epithelial buckling, highlighting an important role for voltage and water regulation in controlling epithelial shape as well as extrusion. Thus, ENaC causes cells with similar membrane potentials to slowly shrink with compression but those with reduced membrane potentials to be eliminated by extrusion, suggesting a chief driver of cell death stems from insufficient energy to maintain cell membrane potential.

cell biology↗

bioRxiv2022

Piezo1 activates non-canonical EGFR endocytosis and signaling

SummaryEGFR-ERK signaling controls cell cycle progression during development, homeostasis, and disease. Both the soluble extracellular ligand, EGF, and mechanical inputs like matrix stiffness, cell adhesion, or stretch activate EGFR-ERK signaling. However, the molecules transducing mechanical forces into EGFR signaling remain unidentified. We previously found that stretch promotes mitosis by mechanically activating the ion channel Piezo1 to trigger ERK signaling. Here, we show that Piezo1 provides the missing link to mechanical EGFR-ERK activation. Both EGF ligand and mechanical or agonist activation of Piezo1 trigger clathrin-mediated endocytosis of EGFR and ERK activation, established markers of EGFR signaling. However, while EGF stimulation requires canonical EGFR tyrosine autophosphorylation, EGFR activation by Piezo1 instead requires Src-p38 kinase-dependent serine EGFR phosphorylation. Additionally, in contrast to the homeostatic signaling downstream EGF activation, direct agonist stimulation of Piezo1 promoted cell cycle re-entry and proliferation in mouse airway epithelia ex vivo via long-term nuclear accumulation of ERK, AP-1 (FOS and JUN), and YAP, typical of regenerative and malignant signaling. Our results suggest two modes of EGFR signaling: basal EGF-dependent signaling via tyrosine autophosphorylation and mechanically activated Piezo1-dependent signaling via serine phosphorylation, resulting in sustained proliferation, critical to repair, regeneration, and cancer growth. Given the limited success of tyrosine kinase inhibitors in cancer, this new axis may provide a more relevant target for cancer treatment.

cell biology↗

bioRxiv2019

Cell cycle S-phase arrest drives cell extrusion

Cell extrusion is a process of cell elimination in which a cell is squeezed out from its tissue of origin. Extrusion occurs in organisms as diverse as sponges, nematodes, insects, fish and mammals. Defective extrusion is linked to many epithelial disorders, including cancer. Despite broad occurrence, cell-intrinsic triggers of extrusion conserved across phyla are generally unknown. We combined genome-wide genetic screens with live-imaging studies of C. elegans embryos and mammalian epithelial cultures and found that S-phase arrest induced extrusion in both. Cells extruded from C. elegans embryos exhibited S-phase arrest, and RNAi treatments that specifically prevent S-phase entry or arrest blocked cell extrusion. Pharmacological induction of S-phase arrest was sufficient to promote cell extrusion from a canine epithelial monolayer. Thus, we have discovered an evolutionarily conserved cell-cycle-dependent trigger of cell extrusion. We suggest that S-phase-arrest induced cell extrusion plays a key role in physiology and disease.

cell biology↗