Phosphorylation and disassembly of intermediate filaments in mitotic cells.

• DOI: 10.1073/pnas.86.6.1885
• Publication Date: 2006-05-31T11:15:03Z
• Authors: Y H Chou; E Rosevear; R D Goldman
• Keywords: Desmin; Phosphopeptide

As baby hamster kidney (BHK-21) cells enter mitosis, networks of intermediate filaments (IFs) are transformed into cytoplasmic aggregates protofilaments. Coincident with this morphological change, the phosphate content vimentin increases from 0.3 mol Pi per protein in interphase to 1.9 mitosis. A similar increase is observed desmin, 0.5 1.5 protein. Fractionation mitotic cell lysates by hydroxylapatite column chromatography reveals presence two IF kinase activities, designated as I and II. Comparison two-dimensional 32P-labeled phosphopeptide maps desmin phosphorylated vivo vitro using partially purified fractions, extensive similarity sets phosphorylation sites. Phosphorylation polymerized IFs II induces complete disassembly determined negative-stain electron microscopy. The results support idea that mitosis regulated its subunit proteins.