Talk about the structure of IFs proteins.

All monomers consist of a helical rod-shaped domain with two globular heads at both ends, two identical or different monomers form a dimer, homodimers or heterodimers formation occurs by winding of the helical domain around each other, dimeric structure has a ropelike shape is polarized since C terminus of one monomer faces C terminus of the other, same for N, dimers then assemble together in an opposite orientation with their heads significantly shifted relative to one another. the resulting tetramer is not polarized since C faces N. Tetramers assemble to form IFs that are not polarized but resistant to tensile (pulling) force.