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Study · In vitro (cells) · 1997

3 results

The actin cytoskeleton is required for receptor-mediated endocytosis in mammalian cells.

Lamaze C, Fujimoto LM, Yin HL, Schmid SL

The Journal of biological chemistry1 Aug 1997Cited by 320 (Europe PMC)

PMID9252336 (opens in a new tab)DOI10.1074/jbc.272.33.20332 (opens in a new tab)PepBankPUB-09252336
Publisher pagePubMedAsk about this study
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Summary

Actin filament organization is essential for endocytosis in yeast. In contrast, the actin-depolymerizing agent cytochalasin D has yielded ambiguous results as to a role for actin in receptor-mediated endocytosis in mammalian cells. We have therefore re-examined this issue using highly specific reagents known to sequester actin monomers. Two of these reagents, thymosin beta4 and DNase I, potently inhibited the sequestration of transferrin receptors into coated pits as measured in a cell-free system using perforated A431 cells. At low concentrations, thymosin beta4 but not DNase I was stimulatory. Importantly, the effects of both reagents were specifically neutralized by the addition of actin monomers. A role for the actin cytoskeleton was also detected in intact cells where latrunculin A, a drug that sequesters actin monomers, inhibited receptor-mediated endocytosis. Biochemical and morphological analyses suggest that these reagents inhibit later events in coated vesicle budding. These results provide new evidence that the actin cytoskeleton is required for receptor-mediated endocytosis in mammalian cells.
CC BYText from Europe PMC. Highlighted sentences are the source of results.

Results from this study3

3 results from studies that gave the peptide. No result from this study comes from people.

  1. 01LabIn vitro (cells)Activity measurement

    In perforated A431 cells, thymosin beta‑4 potently inhibited the sequestration of transferrin receptors into coated pits.

    In plain wordsIn cells, thymosin beta‑4 strongly blocked the movement of transferrin receptors into coated pits.

    Peptide
    Thymosin beta-4 (human)
    Outcome
    DecreaseSequestration of transferrin receptors into coated pits
    Study

    humann: not reported in source

    Perforated A431 cells (cell-free endocytosis system)
    Outcome group
    Receptor activity and mechanism · Whole body
    Studied dose
    Dose not stated

    Source sentences

    Summary
    Two of these reagents, thymosin beta4 and DNase I, potently inhibited the sequestration of transferrin receptors into coated pits as measured in a cell-free system using perforated A431 cells.
  2. 02LabIn vitro (cells)Activity measurement

    In perforated A431 cells, low concentrations of thymosin beta‑4 stimulated receptor sequestration, unlike DNase I.

    In plain wordsIn cells, low amounts of thymosin beta‑4 stimulated this process, but DNase I did not.

    Peptide
    Thymosin beta-4 (human)
    Outcome
    IncreaseSequestration of transferrin receptors at low concentration
    Study

    humann: not reported in source

    Perforated A431 cells (cell-free endocytosis system)
    Outcome group
    Receptor activity and mechanism · Whole body
    Studied dose
    Dose not stated

    Source sentences

    Summary
    At low concentrations, thymosin beta4 but not DNase I was stimulatory.
    1 context sentence
    Summary · context
    Two of these reagents, thymosin beta4 and DNase I, potently inhibited the sequestration of transferrin receptors into coated pits as measured in a cell-free system using perforated A431 cells.
  3. 03LabIn vitro (cells)Mechanism

    In perforated A431 cells, adding actin monomers specifically neutralized the effects of thymosin beta‑4 on receptor sequestration.

    In plain wordsIn cells, adding actin monomers cancelled the effects of thymosin beta‑4, which points to actin binding as the cause.

    Peptide
    Thymosin beta-4 (human)
    Outcome
    Not applicableNeutralization of thymosin beta 4 effect by actin monomers
    Study

    humann: not reported in source

    Perforated A431 cells (cell-free endocytosis system)
    Outcome group
    Receptor activity and mechanism · Whole body
    Studied dose
    Dose not stated

    Source sentences

    Summary
    Importantly, the effects of both reagents were specifically neutralized by the addition of actin monomers.
    1 context sentence
    Summary · context
    Two of these reagents, thymosin beta4 and DNase I, potently inhibited the sequestration of transferrin receptors into coated pits as measured in a cell-free system using perforated A431 cells.

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

  1. Version 2Current

    13 Oct 2026, 01:52 UTC

    Study results updated

  2. Version 1

    12 Oct 2026, 18:17 UTC

    First added · source update from Europe PMC

Subjects

Terms as the source lists them.

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