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  1. Article ; Online: Imaging endocytic vesicle formation at high spatial and temporal resolutions with the pulsed-pH protocol.

    Sposini, Silvia / Rosendale, Morgane / Claverie, Léa / Van, Thi Nhu Ngoc / Jullié, Damien / Perrais, David

    Nature protocols

    2020  Volume 15, Issue 9, Page(s) 3088–3104

    Abstract: Endocytosis is a fundamental process occurring in all eukaryotic cells. Live cell imaging of endocytosis has helped to decipher many of its mechanisms and regulations. With the pulsed-pH (ppH) protocol, one can detect the formation of individual ... ...

    Abstract Endocytosis is a fundamental process occurring in all eukaryotic cells. Live cell imaging of endocytosis has helped to decipher many of its mechanisms and regulations. With the pulsed-pH (ppH) protocol, one can detect the formation of individual endocytic vesicles (EVs) with an unmatched temporal resolution of 2 s. The ppH protocol makes use of cargo protein (e.g., the transferrin receptor) coupled to a pH-sensitive fluorescent protein, such as superecliptic pHluorin (SEP), which is brightly fluorescent at pH 7.4 but not fluorescent at pH <6.0. If the SEP moiety is at the surface, its fluorescence will decrease when cells are exposed to a low pH (5.5) buffer. If the SEP moiety has been internalized, SEP will remain fluorescent even during application of the low pH buffer. Fast perfusion enables the complete exchange of low and high pH extracellular solutions every 2 s, defining the temporal resolution of the technique. Unlike other imaging-based endocytosis assays, the ppH protocol detects EVs without a priori hypotheses on the dynamics of vesicle formation. Here, we explain how the ppH protocol quantifies the endocytic activity of living cells and the recruitment of associated proteins in real time. We provide a step-by-step procedure for expression of the reporter proteins with transient transfection, live cell image acquisition with synchronized pH changes and automated analysis. The whole protocol can be performed in 2 d to provide quantitative information on the endocytic process being studied.
    MeSH term(s) Animals ; Cell Line ; Humans ; Hydrogen-Ion Concentration ; Mice ; Molecular Imaging/methods ; Spatio-Temporal Analysis ; Transport Vesicles/metabolism
    Keywords covid19
    Language English
    Publishing date 2020-08-17
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2244966-8
    ISSN 1750-2799 ; 1754-2189
    ISSN (online) 1750-2799
    ISSN 1754-2189
    DOI 10.1038/s41596-020-0371-z
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Imaging endocytic vesicle formation at high spatial and temporal resolutions with the pulsed-pH protocol

    Sposini, Silvia / Rosendale, Morgane / Claverie, Léa / Van, Thi Nhu Ngoc / Jullié, Damien / Perrais, David

    Nat Protoc

    Abstract: Endocytosis is a fundamental process occurring in all eukaryotic cells. Live cell imaging of endocytosis has helped to decipher many of its mechanisms and regulations. With the pulsed-pH (ppH) protocol, one can detect the formation of individual ... ...

    Abstract Endocytosis is a fundamental process occurring in all eukaryotic cells. Live cell imaging of endocytosis has helped to decipher many of its mechanisms and regulations. With the pulsed-pH (ppH) protocol, one can detect the formation of individual endocytic vesicles (EVs) with an unmatched temporal resolution of 2 s. The ppH protocol makes use of cargo protein (e.g., the transferrin receptor) coupled to a pH-sensitive fluorescent protein, such as superecliptic pHluorin (SEP), which is brightly fluorescent at pH 7.4 but not fluorescent at pH <6.0. If the SEP moiety is at the surface, its fluorescence will decrease when cells are exposed to a low pH (5.5) buffer. If the SEP moiety has been internalized, SEP will remain fluorescent even during application of the low pH buffer. Fast perfusion enables the complete exchange of low and high pH extracellular solutions every 2 s, defining the temporal resolution of the technique. Unlike other imaging-based endocytosis assays, the ppH protocol detects EVs without a priori hypotheses on the dynamics of vesicle formation. Here, we explain how the ppH protocol quantifies the endocytic activity of living cells and the recruitment of associated proteins in real time. We provide a step-by-step procedure for expression of the reporter proteins with transient transfection, live cell image acquisition with synchronized pH changes and automated analysis. The whole protocol can be performed in 2 d to provide quantitative information on the endocytic process being studied.
    Keywords covid19
    Publisher WHO
    Document type Article
    Note WHO #Covidence: #32807908
    Database COVID19

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  3. Article ; Online: Functional recruitment of dynamin requires multimeric interactions for efficient endocytosis.

    Rosendale, Morgane / Van, Thi Nhu Ngoc / Grillo-Bosch, Dolors / Sposini, Silvia / Claverie, Léa / Gauthereau, Isabel / Claverol, Stéphane / Choquet, Daniel / Sainlos, Matthieu / Perrais, David

    Nature communications

    2019  Volume 10, Issue 1, Page(s) 4462

    Abstract: During clathrin mediated endocytosis (CME), the concerted action of dynamin and its interacting partners drives membrane scission. Essential interactions occur between the proline/arginine-rich domain of dynamin (dynPRD) and the Src-homology domain 3 ( ... ...

    Abstract During clathrin mediated endocytosis (CME), the concerted action of dynamin and its interacting partners drives membrane scission. Essential interactions occur between the proline/arginine-rich domain of dynamin (dynPRD) and the Src-homology domain 3 (SH3) of various proteins including amphiphysins. Here we show that multiple SH3 domains must bind simultaneously to dynPRD through three adjacent motifs for dynamin's efficient recruitment and function. First, we show that mutant dynamins modified in a single motif, including the central amphiphysin SH3 (amphSH3) binding motif, partially rescue CME in dynamin triple knock-out cells. However, mutating two motifs largely prevents that ability. Furthermore, we designed divalent dynPRD-derived peptides. These ligands bind multimers of amphSH3 with >100-fold higher affinity than monovalent ones in vitro. Accordingly, dialyzing living cells with these divalent peptides through a patch-clamp pipette blocks CME much more effectively than with monovalent ones. We conclude that dynamin drives vesicle scission via multivalent interactions in cells.
    MeSH term(s) Animals ; Binding Sites ; Clathrin/pharmacology ; Dynamins/chemistry ; Dynamins/genetics ; Dynamins/metabolism ; Endocytosis/drug effects ; Endocytosis/physiology ; Gene Knockout Techniques ; Kinetics ; Ligands ; Mice ; NIH 3T3 Cells ; Protein Binding ; Protein Domains ; Protein Interaction Domains and Motifs ; Proteomics ; src Homology Domains
    Chemical Substances Clathrin ; Ligands ; Dynamins (EC 3.6.5.5)
    Language English
    Publishing date 2019-10-01
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-019-12434-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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