Increased solubility of lamins and redistribution of lamin C in X-linked Emery-Dreifuss muscular dystrophy fibroblasts.
Emery-Dreifuss muscular dystrophy (EDMD) is caused by mutations in the gene encoding the nuclear membrane protein emerin (X-linked EDMD) or in the gene encoding lamins A/C (autosomal dominant EDMD). One hypothesis explaining the disease suggests that the mutations lead to weakness of the nuclear lamina. To test this hypothesis we investigated lamin solubility and distribution in skin fibroblasts from X-EDMD patients. Using in situ extraction of cells and immunofluorescence microscopy or biochemical fractionation and immunoblotting, we found that all lamin subtypes displayed increased solubility properties in fibroblasts from X-EDMD patients compared to normal individuals. Lamin and emerin solubility was mildly increased in fibroblasts from an X-EDMD carrier. Biochemical fractionation and immunoblotting also indicated that lamin C but no other lamin became redistributed from the nuclear lamina to the nucleoplasm in X-EDMD fibroblasts. Indirect immunofluorescence and confocal microscopy studies using lamin A- and lamin C-specific antibodies confirmed that lamin C but not lamin A became redistributed to the nucleoplasm. Interestingly, the lamin A/C binding protein LAP2alpha was also mislocalized in X-EDMD fibroblasts.
Markiewicz
Ewa
E
School of Biological and Biomedical Sciences, University of Durham, South Road, Durham, UK.
Venables
Rachel
R
Mauricio-Alvarez-Reyes
Quinlan
Roy
R
Dorobek
Margareth
M
Hausmanowa-Petrucewicz
Irena
I
Hutchison
Christopher
C
D002467:Cell Nucleus / Q000378:metabolism; D002469:Cell Separation; D041321:Chromosomes, Human, X; D004268:DNA-Binding Proteins / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000378:metabolism*; D005434:Flow Cytometry; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D015151:Immunoblotting; D034904:Lamin Type A / Q000378:metabolism*; D034882:Lamins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D020389:Muscular Dystrophy, Emery-Dreifuss / Q000378:metabolism*; D009154:Mutation; D009685:Nuclear Envelope / Q000378:metabolism; D034881:Nuclear Lamina / Q000378:metabolism; D012259:Ribonuclease, Pancreatic / Q000378:metabolism; D012867:Skin / Q000378:metabolism
D004268:DNA-Binding Proteins; D034904:Lamin Type A; D034882:Lamins; D008565:Membrane Proteins; C440308:lamin C; C093413:lamina-associated polypeptide 2; D003850:Deoxyribonuclease I; D012259:Ribonuclease, Pancreatic