Primary structure analysis and lamin B and DNA binding of human LBR, an integral protein of the nuclear envelope inner membrane

• Published in: The Journal of biological chemistry Vol. 269; no. 15; pp. 11306 - 11311
• Main Authors: QIAN YE, WORMAN, H. J
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 15-04-1994
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Autoantibodies - blood; Bacteriophage lambda - metabolism; Binding and carrier proteins; Binding Sites; Biological and medical sciences; CDC2 Protein Kinase - metabolism; Chickens; Consensus Sequence; Cyclic AMP-Dependent Protein Kinases - metabolism; DNA, Viral - metabolism; DNA-Binding Proteins - metabolism; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; HeLa Cells; Humans; Immunoblotting; Lamin B Receptor; Lamin Type B; Lamins; Liver Cirrhosis, Biliary - immunology; Molecular Sequence Data; Nuclear Envelope - metabolism; Nuclear Proteins - analysis; Nuclear Proteins - chemistry; Nuclear Proteins - metabolism; Phosphorylation; Proteins; Receptors, Cytoplasmic and Nuclear - chemistry; Receptors, Cytoplasmic and Nuclear - metabolism; Recombinant Fusion Proteins - analysis; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - metabolism; Restriction Mapping; Sequence Homology, Amino Acid; Human; Binding protein; Ligand binding; Membrane protein; DNA; Primary structure; Nuclear envelope; Nuclear protein
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(19)78126-5

We have determined the primary structure of human LBR, an integral protein of the nuclear envelope inner membrane, and examined
its interactions with lamin B and DNA. Human LBR is 68% identical to the chicken lamin B receptor and has a basic nucleoplasmic
amino-terminal domain of 208 amino acids followed by a hydrophobic domain with eight putative transmembrane segments. The
amino-terminal domain contains a Ser-Arg-rich stretch and consensus sites for phosphorylation by protein kinase A and p34cdc2
protein kinase. A fusion protein containing the amino-terminal domain of human LBR is recognized by autoantibodies from patients
with primary biliary cirrhosis, and these serum antibodies label the nuclear envelope when examined by immunofluorescence
microscopy. The LBR amino-terminal domain precipitates lamin B from nuclear extracts and retards the migration of double-stranded
DNA subjected to agarose gel electrophoresis. When immobilized on nitrocellulose, the amino-terminal domain of LBR also associates
with DNA, and the stretch between amino acids 71 and 100, which contains the Ser-Arg-rich stretch, is necessary for DNA binding.
These results demonstrate that LBR is conserved among vertebrate species and that its nucleoplasmic domain can potentially
mediate the interaction of both the nuclear lamina and the chromatin with the inner nuclear membrane.