[AndrewC]

because that's how microtubules are used by the cell.

You are certain that is their sole function? In any case, it is not my theory.

[aruanan]

You are certain that is their sole function? In any case, it is not my theory.

They do a lot more than that, but providing highways for transport of other proteins via molecular motors such as dynamin is a major function. Penrose is just going a few more steps toward the nth degree of reductionism.