I also found that recruiting endogous Dynein or an overexpressed Dynein motor domain is sufficient to speed up MT-RF. Recruting a motor deficient point mutant had no effect (see video). I saw the same also for the overexpressed minus-end directed motor domain of KIFC1.
This would suggest that Dynein could speed up MT-RF through microtubules that have their plus-end towards the soma. One result supporting this, is that recruiting Dynein to the plasma membrane speeds up MT-RF in dendrites (50% plus-ends to soma) but not in axons (2% plus-ends to soma).
However, I also recruited two different Kinesin motor domains to the plasma membrane. For both motor domains I saw something like faster MT-RF - with a delay after recruiting them to the membrane. I would say, the jury is still out on whether Dynein or Kinesins drive MT-RF physiologically.
To make matters even more interesting, I also see that inhibiting Myosin II slows down MT-RF (in the middle). This could indicate that Myosin might also somehow be involved in driving MT-RF.
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