that the two proteins that form the coiled-coil bind by hydrophobic interactions. The charged residues in the central domain do not have a major role in the binding of the pair in the central domain.

Cytoplasmic IFs assemble into non-polar unit-length filaments (ULFs). Identical ULFs associate laterally into staggered, antiparallel, soluble tetramers, which associate head-to-tail into protofilaments that pair up laterally into protofibrils,