Dynasore: Selective Dynamin GTPase Inhibitor for Endocytosis Research

Executive Summary: Dynasore (CAS No. 304448-55-3) is a well-characterized, cell-permeable, non-competitive inhibitor of dynamin family GTPases, including dynamin1, dynamin2, and Drp1, with an IC50 of approximately 15 µM (APExBIO product sheet). It selectively and reversibly inhibits dynamin-dependent endocytosis, as demonstrated in multiple cell models (Wang et al. 2018). Dynasore is insoluble in water and ethanol but highly soluble in DMSO, requiring warming or sonication for optimal dissolution. The compound is widely deployed in mechanistic endocytosis research, synaptic vesicle recycling, and signaling studies, but is not suitable where long-term aqueous storage or non-dynamin endocytic pathways are under investigation. This review integrates primary literature, product documentation, and protocol guidance for precise, reproducible research outcomes.

Biological Rationale

Dynamin GTPases are pivotal for membrane fission during clathrin-mediated endocytosis and vesicle trafficking. These processes are fundamental in cellular homeostasis, signal transduction, and pathogen entry (Wang et al. 2018). Dynasore was developed to provide a reversible and selective tool for dissecting dynamin-dependent events without permanently perturbing cellular machinery. Inhibition of dynamin enables researchers to parse the distinct roles of endocytic pathways in health and disease, from neurotransmitter recycling to viral entry.

Mechanism of Action of Dynasore

Dynasore acts as a non-competitive inhibitor of dynamin family GTPases. It binds allosterically, blocking GTP hydrolysis required for membrane scission. This inhibition is reversible and dose-dependent, with an IC50 of ~15 µM for dynamin1/2 and Drp1 (APExBIO). By preventing dynamin-mediated vesicle scission, Dynasore specifically blocks clathrin-mediated endocytosis, as confirmed by reduced transferrin uptake in HeLa and other cell lines (related protocol). The inhibitor does not covalently modify dynamin, allowing for experimental reversibility.

Evidence & Benchmarks

• Dynasore at 80 µM significantly reduces viral entry of GCRV104 and GCRV-JX01 in grass carp kidney (CIK) cells, confirming requirement of dynamin-dependent endocytosis for infection (Wang et al. 2018).
• Transferrin uptake assays in HeLa cells show near-complete inhibition at concentrations ≥80 µM, with partial inhibition observed at 20–40 µM (APExBIO product information).
• Dynasore does not inhibit caveolin- or clathrin-independent endocytosis, as demonstrated by lack of effect on nystatin- or methyl-β-cyclodextrin-sensitive pathways (Wang et al. 2018).
• Reversibility of inhibition is confirmed by washout experiments, with endocytic function restored within 30–60 minutes after compound removal (in-depth analysis).
• Dynasore’s IC50 for dynamin GTPase inhibition is consistently reported as ~15 µM under standard in vitro assay conditions (37°C, pH 7.4, DMSO solvent) (APExBIO).

Applications, Limits & Misconceptions

Dynasore is a pivotal tool for:

• Endocytosis research: Dissecting clathrin/dynamin-dependent pathways in mammalian, fish, and insect models (Wang et al. 2018).
• Synaptic vesicle endocytosis inhibition: Modulating neurotransmitter recycling in neuronal cultures (precision inhibition overview; this review updates with cross-domain viral evidence not present in the linked article).
• Signal transduction pathway study: Parsing the effects of receptor internalization on downstream signaling (benchmark article; this dossier provides updated evidence on mechanism and reversibility).
• Cancer research: Evaluating roles of vesicle trafficking in tumor cell migration and drug delivery (in-depth analysis).

Common Pitfalls or Misconceptions

• Dynasore is not suitable for caveolin-dependent or macropinocytosis studies, as it does not inhibit these pathways (Wang et al. 2018).
• Water or ethanol should not be used as solvents; Dynasore is only soluble in DMSO at ≥16.12 mg/mL (APExBIO).
• Stock solutions should not be stored long-term; prepare fresh aliquots to maintain activity (protocol guidance).
• Non-specific effects at high concentrations (>100 µM) may arise; titrate concentrations to minimize off-target interactions.
• Not recommended for in vivo studies without prior pharmacokinetic validation, as absorption and distribution data are limited (APExBIO).

Workflow Integration & Parameters

Protocol Parameters

• Solubilization: Dissolve in DMSO at ≥16.12 mg/mL; warm to 37°C or use ultrasonic shaking for complete dissolution (APExBIO).
• Working concentration: Typical range is 20–80 µM; benchmark studies commonly use 80 µM for near-complete inhibition (Wang et al. 2018).
• Preincubation: 30 minutes prior to endocytic challenge is standard in cellular assays.
• Control conditions: Include DMSO-only and washout arms to confirm reversibility and specificity.
• Storage: Store powder and DMSO stock at -20°C; avoid repeated freeze-thaw cycles and long-term solution storage (protocol guidance).

Conclusion & Outlook

Dynasore, as supplied by APExBIO, remains the benchmark non-competitive dynamin GTPase inhibitor for dissecting clathrin-mediated endocytosis in cellular and molecular research. Its robust, reversible inhibition profile is validated across diverse models, including virology, neuroscience, and cancer cell biology. While alternative inhibitors and genetic approaches exist, Dynasore's unique combination of selectivity, reversibility, and ease of use underpins its continued relevance. Future research integrating Dynasore with live-cell imaging and single-vesicle assays will further resolve the spatiotemporal dynamics of dynamin-mediated events. All conclusions are grounded in the cited primary literature and supplier data, without extrapolation beyond validated domains.