The diameter of the cytoskeletal fibers are as follows -
Microtubules about 25 nano meters
actin filaments/micro filaments is about 7 nano meters
intermediate filaments about 8 to 10 nano meters
Hence ,
From the above data , Microtubules have the largest diameter , it is made up of tubulin proteins which are arrange in the form of a straw - like tube which is hollow from inside , and each of the tubuline protein consists of two sub units i.e. alpha - tubuline and the beta - tubuline .