TY - JOUR
T1 - Stabilization of the spectrin-like domains of nesprin-1α by the evolutionarily conserved "adaptive" domain
AU - Zhong, Zhixia
AU - Chang, Siwei A.
AU - Kalinowski, Agnieszka
AU - Wilson, Katherine L.
AU - Dahl, Kris Noel
N1 - Funding Information:
We gratefully acknowledge E. McNally (Univ. Chicago) for the nesprin-1α constructs, and colleagues at Carnegie Mellon: S. D. Chapman for help with recombinant protein production, T. Przybycien for advice and CD equipment, L. Walker for help with DLS, and A. M. Laurent and V. Lam for advice. This research was supported by funding from NIH (GM48646 to K.L.W.), a National Research Service Award Fellowship (F32 GM074502 to K.N.D.) and a Liang Jidian Fellowship (to Z.Z.).
PY - 2010/6
Y1 - 2010/6
N2 - Nesprins are located at the outer and inner membranes of the nuclear envelope and help link the cytoskeleton to the nucleoskeleton. Nesprin-1α, located at the inner nuclear membrane, binds to A-type lamins and emerin and has homology to spectrin-repeat proteins. However, the mechanical and thermodynamic properties of the spectrin-like repeats (SLRs) of nesprin-1α and the potential structural contributions of the unique central domain were untested. In other spectrin superfamily proteins, tandem spectrin-repeat domains undergo cooperatively coupled folding and unfolding. We hypothesized that the large central domain, which interrupts SLRs and is conserved in other nesprin isoforms, might confer unique structural properties. To test this model we measured the thermal unfolding of nesprin-1α fragments using circular dichroism and dynamic light scattering. The SLRs in nesprin-1α were found to have structural and thermodynamic properties typical of spectrins. The central domain had relatively little secondary structure as an isolated fragment, but significantly stabilized larger SLR-containing molecules by increasing their overall helicity, thermal stability and cooperativity of folding. We suggest this domain, now termed the "adaptive" domain (AD), also strengthens dimerization and inhibits unfolding. Further engineering of the isolated AD, and AD-containing nesprin molecules, may yield new information about the higher-order association of cooperative protein motifs.
AB - Nesprins are located at the outer and inner membranes of the nuclear envelope and help link the cytoskeleton to the nucleoskeleton. Nesprin-1α, located at the inner nuclear membrane, binds to A-type lamins and emerin and has homology to spectrin-repeat proteins. However, the mechanical and thermodynamic properties of the spectrin-like repeats (SLRs) of nesprin-1α and the potential structural contributions of the unique central domain were untested. In other spectrin superfamily proteins, tandem spectrin-repeat domains undergo cooperatively coupled folding and unfolding. We hypothesized that the large central domain, which interrupts SLRs and is conserved in other nesprin isoforms, might confer unique structural properties. To test this model we measured the thermal unfolding of nesprin-1α fragments using circular dichroism and dynamic light scattering. The SLRs in nesprin-1α were found to have structural and thermodynamic properties typical of spectrins. The central domain had relatively little secondary structure as an isolated fragment, but significantly stabilized larger SLR-containing molecules by increasing their overall helicity, thermal stability and cooperativity of folding. We suggest this domain, now termed the "adaptive" domain (AD), also strengthens dimerization and inhibits unfolding. Further engineering of the isolated AD, and AD-containing nesprin molecules, may yield new information about the higher-order association of cooperative protein motifs.
KW - Emerin
KW - LINC complex
KW - Laminopathy
KW - Nuclear envelope
KW - Nuclear mechanics
KW - Spectrin repeat
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U2 - 10.1007/s12195-010-0121-3
DO - 10.1007/s12195-010-0121-3
M3 - Article
C2 - 20563238
AN - SCOPUS:77955661779
SN - 1865-5025
VL - 3
SP - 139
EP - 150
JO - Cellular and Molecular Bioengineering
JF - Cellular and Molecular Bioengineering
IS - 2
ER -