title: Nesprin-1alpha self-associates and binds directly to emerin and lamin A in vitro.
abstract: Nesprin-1alpha is a spectrin repeat (SR)-containing, transmembrane protein of the inner nuclear membrane, and is highly expressed in muscle cells. A yeast two-hybrid screen for nesprin-1alpha-interacting proteins showed that nesprin-1alpha interacted with itself. Blot overlay experiments revealed that nesprin-1alpha's third SR binds the fifth SR. The carboxy-terminal half of nesprin-1alpha directly bound lamin A, a nuclear intermediate filament protein. Biochemical analysis demonstrated that nesprin-1alpha dimers bind directly to the nucleoplasmic domain of emerin, an inner nuclear membrane protein, with an affinity of 4 nM. Binding was optimal for full nucleoplasmic dimers of nesprin-1alpha, since nesprin fragments SR1-5 and SR5-7 bound emerin as monomers with affinities of 53 nM and 250 mM, respectively. We propose that membrane-anchored nesprin-1alpha antiparallel dimers interact with both emerin and lamin A to provide scaffolding at the inner nuclear membrane.
authors.affiliation: Department of Pathology, The University of Chicago, Chicago, IL 60637, USA.
authors.forename: John M K
authors.initials: JM
authors.lastname: Mislow
authors.forename: James M
authors.initials: JM
authors.lastname: Holaska
authors.forename: Marian S
authors.initials: MS
authors.lastname: Kim
authors.forename: Kenneth K
authors.initials: KK
authors.lastname: Lee
authors.forename: Miriam
authors.initials: M
authors.lastname: Segura-Totten
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Wilson
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: McNally
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism; D019281:Dimerization; D006801:Humans; D034904:Lamin Type A; D034882:Lamins; D008565:Membrane Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins; D009685:Nuclear Envelope / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D016601:RNA-Binding Proteins; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013946:Thymopoietins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: C061886:ABF1 protein, S cerevisiae; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D034904:Lamin Type A; D034882:Lamins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D010446:Peptide Fragments; D016601:RNA-Binding Proteins; C415465:SYNE1 protein, human; D029701:Saccharomyces cerevisiae Proteins; D013946:Thymopoietins; D014157:Transcription Factors; C092710:emerin