Keratins, neurofilaments, and vimentins are all categories of intermediate filaments. Which of the following properties below is not true of these types of intermediate filaments?
(a) They strengthen cells against mechanical stress.
(b) Dimers associate by noncovalent bonding to form a tetramer.
(c) They are found in the cytoplasm.
(d) Phosphorylation causes disassembly during every mitotic cycle.