title: Unconventional actin conformations localize on intermediate filaments in mitosis.
abstract: Different structural conformations of actin have been identified in cells and shown to reside in distinct subcellular locations of cells. In this report, we describe the localization of actin on a cage-like structure in metaphase HEK 293T cells. Actin was detected with the anti-actin antibodies 1C7 and 2G2, but not with the anti-actin antibody C4. Actin contained in this structure is independent of microtubules and actin filaments, and colocalizes with vimentin. Taking advantage of intermediate filament collapse into a perinuclear dense mass of cables when microtubules are depolymerized, we were able to relocalize actin to such structures. We hypothesize that phosphorylation of intermediate filaments at mitosis entry triggers the recruitment of different actin conformations to mitotic intermediate filaments. Storage and partition of the nuclear actin and antiparallel "lower dimer" actin conformations between daughter cells possibly contribute to gene transcription and transient actin filament dynamics at G1 entry.
authors.affiliation: Department of Medical Protein Research, VIB, Ghent University, Faculty of Medicine and Health Sciences, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hubert
authors.forename: Joël
authors.initials: J
authors.lastname: Vandekerckhove
authors.forename: Jan
authors.initials: J
authors.lastname: Gettemans
mesh_terms: D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D007382:Intermediate Filaments / Q000378:metabolism*; D008938:Mitosis; D011487:Protein Conformation
chemical_list: D000199:Actins