Disassembly of Intermediate Filaments

The assembly and disassembly of intermediate filaments are regulated by post-translational modifications, most commonly phosphorylation by kinases and dephosphorylation by phosphatases.

Site-specific phosphorylation at the N-terminal head domain alters the conformation of the intermediate filaments to promote disassembly of preformed filaments, and prevent further assembly.

Additionally, because intermediate filaments are packed in a dense cytoskeletal mesh, kinases in close proximity cross-activates each other, increasing intermediate filament phosphorylation, triggering their disassembly.

During mitosis, two types of intermediate filaments, vimentin and nuclear lamins, help break down the nuclear membrane.

These intermediate filaments are phosphorylated on specific serines on the N-terminal head domain in vimentin and on either side of the central rod domain in lamins.

These post-translational modifications trigger the disassembly of  intermediate filaments, resulting in the disintegration of the nuclear membrane.

The depolymerized lamin dimers remain anchored to the fragmented nuclear membrane through the covalent attachment of prenyl groups. As the cell cycle progresses into telophase, dephosphorylation of lamins allows nuclear envelope reassembly in the daughter cells.