Dynasore: Noncompetitive Dynamin GTPase Inhibitor for Endocytosis Research

Executive Summary: Dynasore is a cell-permeable, noncompetitive inhibitor of dynamin GTPase activity with an IC50 of 15 µM, targeting dynamin1, dynamin2, and Drp1 (APExBIO product page). It blocks dynamin-dependent endocytosis, including transferrin uptake and synaptic vesicle recycling, in a reversible manner (Wang et al. 2018). Its rapid action makes it integral for dissecting vesicle trafficking and signal transduction in mammalian and aquatic models. Dynasore is insoluble in water and ethanol, requiring DMSO for preparation and optimal solubility. Extensive benchmarking supports its application in cancer, neurodegenerative, and virology research (internal review).

Biological Rationale

Dynamin is a large GTPase required for endocytic vesicle scission from the plasma membrane (Wang et al. 2018). Its activity underlies critical cellular processes such as receptor-mediated endocytosis, synaptic vesicle recycling, and membrane protein trafficking. Disruption of dynamin function impairs clathrin-mediated endocytosis, affecting nutrient uptake, signal transduction, and pathogen entry. Inhibition of dynamin GTPase activity provides a robust method to investigate endocytosis and downstream effects in both normal physiology and disease models (related article). This article provides a detailed, factual update on prior reviews by focusing on the quantitative pharmacology and validated model systems for Dynasore.

Mechanism of Action of Dynasore

Dynasore is a noncompetitive inhibitor of dynamin GTPase activity. It binds to the GTPase domain of dynamin1, dynamin2, and Drp1, blocking GTP hydrolysis without competing with substrate binding (APExBIO). The IC50 for dynamin GTPase inhibition is 15 µM, established using purified enzyme assays at 25°C and pH 7.4. This inhibition is rapid and reversible, allowing time-resolved studies of endocytosis. Dynasore's action is independent of clathrin or accessory proteins, directly targeting the dynamin GTPase catalytic cycle. The compound is effective in multiple cell types, including neurons and HL-1 cardiomyocytes, and disrupts transferrin uptake within 5–15 minutes of treatment at 37°C (internal review). In viral entry studies, such as with grass carp reovirus, Dynasore blocks clathrin-mediated and dynamin-dependent endocytic pathways essential for infection (Wang et al. 2018).

Evidence & Benchmarks

• Dynasore at 80 µM inhibits clathrin-mediated endocytosis in grass carp kidney (CIK) cells, leading to significant reduction in viral entry (Wang et al. 2018, DOI).
• IC50 for dynamin GTPase inhibition is consistently measured at 15 µM using in vitro GTP hydrolysis assays at 25°C, pH 7.4 (APExBIO).
• Dynasore blocks transferrin uptake and synaptic vesicle endocytosis in mammalian neurons within 5–15 minutes at 37°C, confirmed by fluorescence microscopy (internal).
• The inhibition by Dynasore is fully reversible within 30 minutes of compound washout, allowing dynamic recovery studies (internal article).
• Dynasore is insoluble in water and ethanol but achieves ≥16.12 mg/mL solubility in DMSO when warmed to 37°C or sonicated (APExBIO product documentation, link).
• The compound shows no significant inhibition of caveolin-dependent or macropinocytosis pathways at concentrations below 100 µM (Wang et al. 2018, DOI).

Applications, Limits & Misconceptions

Dynasore is a principal tool for delineating dynamin-dependent endocytosis in mammalian, aquatic, and microbial systems. Its applications include:

• Analysis of receptor-mediated endocytosis and vesicle trafficking.
• Functional studies in cancer cell signaling and neurodegenerative disease models (internal review; this article provides updated quantitative use cases and clarifies protocol-specific caveats).
• Viral entry and host-pathogen interaction studies, especially for viruses utilizing clathrin-mediated endocytosis, such as GCRV (Wang et al. 2018).
• Time-resolved investigation of synaptic vesicle cycling in neurons.

Common Pitfalls or Misconceptions

• Dynasore does not inhibit caveolin-dependent or macropinocytic pathways at recommended concentrations (<100 µM) (DOI).
• Solubility issues may arise if not prepared in DMSO; water or ethanol are unsuitable solvents (APExBIO).
• Prolonged exposure (>2 hours) or high concentrations (>100 µM) can cause off-target effects unrelated to dynamin inhibition.
• Dynasore should not be used as an antiviral agent for therapeutic purposes; it is strictly for research use.
• Reversibility of inhibition may confound long-term endpoint assays if not controlled for washout effects.

Workflow Integration & Parameters

For optimal results, Dynasore (A1605) from APExBIO should be dissolved in DMSO at ≥16.12 mg/mL. The stock should be warmed to 37°C or sonicated to ensure full dissolution. Working solutions are prepared by diluting stock into culture medium, maintaining a final DMSO concentration <0.5% (v/v). Recommended working concentrations are 20–80 µM for most cell systems, with exposure times of 5–30 minutes for acute inhibition. For long-term studies, washout and recovery protocols should be validated. Store Dynasore as a solid or DMSO stock at -20°C for up to several months (product page). This workflow extends the detailed experimental integration described in recent reviews by specifying exact solubility and handling parameters for reproducibility.

Conclusion & Outlook

Dynasore is a benchmark noncompetitive inhibitor for dissecting dynamin-dependent endocytosis and vesicle trafficking pathways. Its rapid, reversible action, validated selectivity, and robust use in diverse models make it indispensable for studies in cell signaling, virology, cancer, and neuroscience. Ongoing research is expanding its application to complex disease and microbial systems. For detailed product specifications and ordering, see the Dynasore A1605 kit from APExBIO.