Dyngo-4a

Dynamin GTPase assay:

Dynamin I activity is measured in its SAI activity state or is stimulated by three different methods. As each stimulus activates dynamin to different extents, each assay requires different dynamin concentrations. First, maximal dynamin activity is stimulated by sonicated PS liposomes. Purified dynamin I (10–20 nM, diluted in: 6 mM Tris–HCl, 20 mM NaCl and 0.01% Tween 80, pH 7.4) is incubated in 96-well plates in GTPase buffer (5 mM Tris–HCl, 10 mM NaCl, 2 mM Mg²⁺, 0.05% Tween 80, pH 7.4, 1 µg/mL leupeptin and 0.1 mM PMSF) and GTP 0.3 mM in the presence of test compound for 30 min at 37°C in a final assay volume of 150 μL. Reactions are terminated with 10 μL of 0.5 M ethylenediaminetetraacetic acid (EDTA) pH 7.4 and Malachite Green solution (40 μL: 2% w/v ammonium molybdate tetrahydrate, 0.15% w/v malachite green and 4 M HCl) is added for 5 min. Second, dynamin (20 nM) is stimulated by 10 µg/mL of taxol-stabilized preformed bovine brain microtubules using the same protocol. Third, dynamin I (50 nM) is stimulated by 1 μM of recombinant grb2, a SH3-containing protein that stimulates dynamin about 5–10 times less efficiently than liposomes or microtubules. Finally, dynamin (500 nM) SAI activity is measured using high concentrations of dynamin, which promote its cooperative self-assembly into rings (but not helices). The final DMSO concentration in the GTPase or endocytosis assays is at most 3.3 or 1%, respectively, but typically is at 1%. The GTPase assay for dynamin I is unaffected by DMSO up to 3.3%. Compounds are dissolved as 30 mM stocks in 100% DMSO. These stock solutions can be stored at −20°C for several months. Compounds are subsequently diluted into solutions of 50% DMSO made up in 20 mM Tris–HCl pH 7.4 and diluted again into the final assay. For analysis of the kinetics of 4a inhibition, dynamin I at a final concentration of 17 nM is incubated with GTPase buffer containing PS (2 µg/mL) and varying amounts of GTP (50–250 μM) in the presence of 4a at a concentration range between 0.5 and 6 μM. The reaction is stopped after 30 min by addition of EDTA (0.5 mM, pH 7.4). Curves are generated using the Michaelis–Menten equation v = Vmax[S]/(Km + [S]), where S is the GTP substrate. After the Vmax and Km values were determined, the data were transformed using the Lineweaver–Burke equation, 1/v = 1/Vmax + (Km/Vmax)(1/[S]). Assay conditions are based on the dynamin I assay but contained modifications. Recombinant dynamin II is used at 50 nM, stimulated by 10 µg/mL PS. The GTPase reaction is allowed to occur for 90 min at 37°C before termination.

• Cell lines: αT3–1 or LβT2 cells
• Concentrations: 30 μM
• Incubation Time: 30 minutes
• Method:

  αT3-1 or LβT2 cells (2 × 10⁶) were grown overnight in a 6-well culture dish and then serum starved for 2–4 hours. Cells were pretreated with either vehicle (0), dynasore (80μM), or dyngo (30μM) for 30 minutes. For dose-response studies, indicated doses of dynasore were used for a 30-minute pretreatment. After pretreatment, cells were treated with 0 or GnRHa (10 nM) for 10 minutes. Cells were then washed twice in PBS, lysed in radio-immunoprecipitation assay (RIPA) buffer and subjected to SDS-PAGE (acrylamide:bis-acrylamide ratio of 29:1) and electroblotted to polyvinylidene difluoride membranes.

  
  (Only for Reference)

• Animal Models: Female CD-1 mice
• Dosages: 30 mg/kg
• Administration: i.p.
  (Only for Reference)