Nesprin-1alpha self-associates and binds directly to emerin and lamin A in vitro.
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.
Mislow
John M K
JM
Department of Pathology, The University of Chicago, Chicago, IL 60637, USA.
Holaska
James M
JM
Kim
Marian S
MS
Lee
Kenneth K
KK
Segura-Totten
Miriam
M
Wilson
Katherine L
KL
McNally
Elizabeth M
EM
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
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