title: Lamin B constitutes an intermediate filament attachment site at the nuclear envelope.
abstract: We found that urea extraction of turkey erythrocyte nuclear envelopes abolished their ability to bind exogenous 125I-vimentin, while, at the same time, it removed the nuclear lamins from the membranes. After purification of the lamins from such urea extracts, a specific binding between isolated vimentin and lamin B, or a lamin A + B hetero-oligomer, was detected by affinity chromatography. Similar analysis revealed that the 6.6-kD vimentin tail piece was involved in this interaction. By other approaches (quantitative immunoprecipitation, rate zonal sedimentation, turbidometric assays) a substoichiometric lamin B-vimentin binding was determined under in vitro conditions. It was also observed that anti-lamin B antibodies but not other sera (anti-lamin A, anti-ankyrin, preimmune) were able to block 70% of the binding of 125I-vimentin to native, vimentin-depleted, nuclear envelopes. These data, which were confirmed by using rat liver nuclear lamins, indicate that intermediate filaments may be anchored directly to the nuclear lamina, providing a continuous network connecting the plasma membrane skeleton with the karyoskeleton of eukaryotic cells.
authors.forename: S D
authors.initials: SD
authors.lastname: Georgatos
authors.forename: G
authors.initials: G
authors.lastname: Blobel
mesh_terms: D000818:Animals; D001665:Binding Sites; D002846:Chromatography, Affinity; D003599:Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure*; D007158:Immunologic Techniques; D007382:Intermediate Filaments / Q000378:metabolism* / Q000648:ultrastructure; D034904:Lamin Type A; D034921:Lamin Type B; D034882:Lamins; D009391:Nephelometry and Turbidimetry; D009685:Nuclear Envelope / Q000378:metabolism* / Q000648:ultrastructure; D009698:Nucleoproteins / Q000276:immunology / Q000502:physiology*; D011485:Protein Binding; D051381:Rats; D014422:Turkeys; D014746:Vimentin / Q000378:metabolism*
chemical_list: D034904:Lamin Type A; D034921:Lamin Type B; D034882:Lamins; D009698:Nucleoproteins; D014746:Vimentin