You have purified a protein, MT1, that binds only to GTP-bound tubulin. You proc

Question

You have purified a protein, MT1, that binds only to GTP-bound tubulin. You proceed to fuse MT1 to GFP and find that the fusion of GFP to MT1 does not disrupt MT1 function in any way (good news!). You use a different dye to label the microtubules in red so that you can visualize MT1-GFP and the microtubules at the same time. (Note that the red dye does not affect the microtubule’s properties.) A. If you were to polymerize some red-labeled microtubules in a dish, would you expect MT1-GFP to be associated with one or both ends of a microtubule, with the middle of the microtubule, or be evenly distributed throughout the microtubule? Explain. B. If you were to take time-lapse images in which you visualize only MT1- GFP (and not microtubules), what would you expect to see? Describe what you think would happen to MT1-GFP over time with respect to its localization inside of this cell.

Explanation / Answer

A) GTP-bound tubulin dimers bind to the growing end (+ end) of microtubule and as the microtubule grows GTP bound to tubulin dimers gets dephosphorylated to GDP. As MT1 protein bind only to the GTP-bound tubulin, I would expect MT1 to be associated with the growing end (+ end) of the microtubule.

B) I would expect to see the movement of GFP tagged MT1 from one direction to another direction (like a glowing dot moving in a particular direction)

C) Since cells has continuous polymerization and depolymerization of microtubules, MT1-GFP keeps binding and moving along the growing end of microtubules. In cell you can see random movement of MT1 all over the cytoplasm.

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.