The mechanism of dynamin activity is not fully understood. Thereare two schools of thought on the matter. The first one suggeststhat the GTPase activity of dynamin allows dynamin to pinch off theneck of the vesicle. The other suggests that the GTP-bound form ofdynamin acts as a signal to recruit other enzymes that actually dothe pinching of the membrane. Since you are a cell biology stud,you decide to do an experiment to answer this questiononce-and-for-all. To do this, you prepare a mutated form of thedynamin gene that prevents it from hydrolyzing its bound GTP. Youthen perform an experiment where you express the mutated dynamingene, along with the proper controls, in animal cells lacking afunctional, endogenous dynamin gene and analyze the ability ofthose cells to form clathrin-coated vesicles. Answer the followingquestions using the data when necessary.
Cells expressing... Result wild-type dynamin + mutant dynamin + no dynamin -
A. In what state is the mutant dynamin â active or inactive? In2-3 sentences, explain why you chose that answer.
B. Which of the two schools of thought does the data support?USE THE DATA GIVEN to explain your answer in 2-3 sentences.
C. What would the data look like if the other school of thoughtwas supported? Explain why in 2-3 sentences.
The mechanism of dynamin activity is not fully understood. Thereare two schools of thought on the matter. The first one suggeststhat the GTPase activity of dynamin allows dynamin to pinch off theneck of the vesicle. The other suggests that the GTP-bound form ofdynamin acts as a signal to recruit other enzymes that actually dothe pinching of the membrane. Since you are a cell biology stud,you decide to do an experiment to answer this questiononce-and-for-all. To do this, you prepare a mutated form of thedynamin gene that prevents it from hydrolyzing its bound GTP. Youthen perform an experiment where you express the mutated dynamingene, along with the proper controls, in animal cells lacking afunctional, endogenous dynamin gene and analyze the ability ofthose cells to form clathrin-coated vesicles. Answer the followingquestions using the data when necessary.
| Cells expressing... | Result |
| wild-type dynamin | + |
| mutant dynamin | + |
| no dynamin | - |
A. In what state is the mutant dynamin â active or inactive? In2-3 sentences, explain why you chose that answer.
B. Which of the two schools of thought does the data support?USE THE DATA GIVEN to explain your answer in 2-3 sentences.
C. What would the data look like if the other school of thoughtwas supported? Explain why in 2-3 sentences.
