Journal: bioRxiv
Article Title: Filopodia-mediated trans-endocytosis
doi: 10.64898/2026.02.09.703982
Figure Lengend Snippet: ( A-I ) DCIS.com cells expressing MYO10 HMM -GFP were mixed with parental cells and grown as a monolayer. After 24 h, cells were fixed, labelled to visualise the plasma membrane and nuclei (DAPI), and imaged using high-resolution Airyscan fluorescence microscopy and focused-ion-beam scanning electron microscopy (FIB-SEM). ( A ) Representative registration and alignment of the fluorescence and FIB-SEM datasets. ( B ) Examples of internalised MYO10-positive filopodia tips identified and manually segmented from the FIB-SEM volume. ( C ) Quantification of the volume of internalised filopodia tips based on manual segmentation (n = 47 internalised filopodia tips, two biological replicates). ( D ) Representative FIB-SEM image showing an internalised MYO10-positive filopodia tip displaying a double-membrane structure. ( E ) Pie chart quantifying the proportion of internalised filopodia tips exhibiting two clearly visible membranes and a discernible lumen (n = 47 internalised filopodia tips, two biological replicates). ( F ) Quantification of the percentage of internalised filopodia tips in contact with endoplasmic reticulum (ER) tubules or mitochondria, as assessed from segmented FIB-SEM volumes (n = 47 internalised filopodia tips, two biological replicates). ( G ) Three-dimensional rendering of an internalised filopodia tip (magenta) in close association with ER tubules (green). ( H ) High-resolution Airyscan image showing an internalised filopodia tip in proximity to ER structures. ( I ) Representative electron microscopy images illustrating the ultrastructural diversity of internalised MYO10-positive filopodia tips. ( J ) DCIS.com cells expressing MYO10 HMM -GFP were mixed with parental cells and cultured as a monolayer for 24 hours. Cells were then treated with concanamycin A (125 nM) for 24 hours. Subsequently, cells were fixed, stained for LAMP2, and imaged using an Airyscan confocal microscope. Representative images and quantification of the impact of lysosomal inhibition on the number of MYO10 HMM dots associated with recipient cells, as well as the percentage of MYO10 HMM dots overlapping with LAMP2 staining, are shown (4 biological replicates, 47 fields of view). Quantification was carried out per field of view, excluding the MYO10 HMM -GFP-expressing cell; only MYO10 HMM dots associated with neighbouring parental cells were analysed (see Methods). ( C, J ) Data are presented as boxplots, with whiskers extending from the 10th to the 90th percentiles. Boxes indicate the interquartile range, and the central line denotes the median. Data points outside the whiskers are shown as individual dots. The raw images used to generate this figure have been archived on Zenodo .
Article Snippet: Additional reagents used in this study include wheat germ agglutinin (WGA, ThermoFisher Scientific, W32466), ER-TrackerTM Red (ThermoFisher Scientific, E34250), SiR-lysosome (Spirochrome, SC012), Dyngo4a (Hydroxy-Dynasore) (Abcam, AB120689), DAPI (ThermoFisher Scientific, D1306), Alexa Fluor 647-conjugated phalloidin (Invitrogen, A30107), Poly-D-Lysine (GibcoTM, A3890401), Alexa Fluor 647-conjugated Concanavalin A (ThermoFisher Scientific, C21421), Concanamycin A (Santa Cruz Biotechnology, sc-202111A), and fibronectin (Sigma-Aldrich, 341631).
Techniques: Expressing, Clinical Proteomics, Membrane, Fluorescence, Microscopy, Electron Microscopy, Cell Culture, Staining, Inhibition