Actin polymerisation at the cytoplasmic face of eukaryotic nuclei.
BACKGROUND
There exists abundant molecular and ultra-structural evidence to suggest that cytoplasmic actin can physically interact with the nuclear envelope (NE) membrane system. However, this interaction has yet to be characterised in living interphase cells.


RESULTS
Using a fluorescent conjugate of the actin binding drug cytochalasin D (CD-BODIPY) we provide evidence that polymerising actin accumulates in vicinity to the NE. In addition, both transiently expressed fluorescent actin and cytoplasmic micro-injection of fluorescent actin resulted in accumulation of actin at the NE-membrane. Consistent with the idea that the cytoplasmic phase of NE-membranes can support this novel pool of perinuclear actin polymerisation we show that isolated, intact, differentiated primary hepatocyte nuclei support actin polymerisation in vitro. Further this phenomenon was inhibited by treatments hindering steric access to outer-nuclear-membrane proteins (e.g. wheat germ agglutinin, anti-nesprin and anti-nucleoporin antibodies).


CONCLUSIONS
We conclude that actin polymerisation occurs around interphase nuclei of living cells at the cytoplasmic phase of NE-membranes.
Münter
Sylvia
S
Unité de Biologie Cellulaire du Noyau, CNRS URA 2582, Département de Biologie Cellulaire et Infection, Institut Pasteur, 25, Rue du Docteur Roux, 75724 Paris Cedex 15, France. sylvia.muenter@med.uni-heidelberg.de
Enninga
Jost
J
Vazquez-Martinez
Rafael
R
Delbarre
Erwan
E
David-Watine
Brigitte
B
Nehrbass
Ulf
U
Shorte
Spencer L
SL
D000199:Actins / Q000737:chemistry*; D000818:Animals; D001665:Binding Sites; D001704:Biopolymers; D001896:Boron Compounds / Q000032:analysis; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002942:Circular Dichroism; D015638:Cytochalasin D / Q000494:pharmacology; D047630:Depsipeptides / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000032:analysis; D006367:HeLa Cells; D006801:Humans; D008099:Liver / Q000648:ultrastructure; D009685:Nuclear Envelope / Q000737:chemistry*; D011817:Rabbits; D051381:Rats; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D000199:Actins; D001704:Biopolymers; D001896:Boron Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D047630:Depsipeptides; D005456:Fluorescent Dyes; D013844:Thiazoles; D053778:Thiazolidines; C057531:jasplakinolide; D015638:Cytochalasin D; C037067:latrunculin A