Question

You find that the polarity of microtubules in the alternate universe cilia is the opposite of the polarity of the microtubules in cilia from your body. Describe the arrangement of the microtubules of these alternate universe cilia. Also, describe possible steps for the process of intraflagellar transport in these alternate universe cilia.

Answer 1

Microtubules have polarity, they are formed by small units called tubulins that dimerize to form the microtubule. The polymerized microtubules have minus or plus polarity, in our universe the minus pole is the one that attaches to the centrosome (the organelle that works for microtubule arrangement) and the plus pole is the one that polymerizes and extends. This means that in the alternative universe the plus pole is anchored to the centrosome and the minus pole is the one extending.

The intraflagellar transport its a process that create and maintain cillia active. In this process, kinesin and dynein proteins carry proteins into the cillia using the internal microtubules, they take the proteins in and out of the cillia. In our universe the kinesins walk towards the cillia, while the dyneins walk back from the cillia, this occurs because kinesins can walk from - to +, while dyneins can walk from + to -.

In our alternative universi we would found an intraflagellar transport that uses dyneins to walk into the cillia and towards the cillia tip, and kinesins that return from the cillia into the cell body, just the opposite as in our own universe.