title: Dynamics and Structure-Function Relationships of the Lamin B Receptor (LBR).
abstract: The lamin B receptor (LBR) is a multi-spanning membrane protein of the inner nuclear membrane that is often employed as a "reporter" of nuclear envelope dynamics. We show here that the diffusional mobility of full-length LBR exhibits significant regional variation along the nuclear envelope, consistent with the existence of discrete LBR microdomains and the occurrence of multiple, asymmetrically-spaced anastomoses along the nuclear envelope-endoplasmic reticulum interface. Interestingly, a commonly used fusion protein that contains the amino-terminal region and the first transmembrane domain of LBR exhibits reduced mobility at the nuclear envelope, but behaves similarly to full-length LBR in the endoplasmic reticulum. On the other hand, carboxy-terminally truncated mutants that retain the first four transmembrane domains and a part or the whole of the amino-terminal region of LBR are generally hyper-mobile. These results suggest that LBR dynamics is structure and compartment specific. They also indicate that native LBR is probably "configured" by long-range interactions that involve the loops between adjacent transmembrane domains and parts of the amino-terminal region.
authors.affiliation: Stem Cell and Chromatin Group, The Institute of Molecular Biology and Biotechnology, Biomedical Division, FORTH-ITE, Heraklion, Crete, Greece.|The Laboratory of Biology, The University of Ioannina, School of Medicine, Ioannina, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Giannios
authors.affiliation: Stem Cell and Chromatin Group, The Institute of Molecular Biology and Biotechnology, Biomedical Division, FORTH-ITE, Heraklion, Crete, Greece.|The Laboratory of Biology, The University of Ioannina, School of Medicine, Ioannina, Greece.
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Chatzantonaki
authors.affiliation: Stem Cell and Chromatin Group, The Institute of Molecular Biology and Biotechnology, Biomedical Division, FORTH-ITE, Heraklion, Crete, Greece.|The Laboratory of Biology, The University of Ioannina, School of Medicine, Ioannina, Greece.
authors.forename: Spyros
authors.initials: S
authors.lastname: Georgatos
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000378:metabolism; D036681:Fluorescence Recovery After Photobleaching; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D051379:Mice; D009038:Motion; D009154:Mutation; D009685:Nuclear Envelope / Q000378:metabolism; D000072417:Protein Domains; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D017384:Sequence Deletion; D013329:Structure-Activity Relationship; D014162:Transfection; D000097682:Lamin B Receptor
chemical_list: D001426:Bacterial Proteins; D008164:Luminescent Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins; D000097682:Lamin B Receptor; C054562:yellow fluorescent protein, Bacteria