Title: Characterization of the Head-to-Tail Overlap Complexes Formed by Human Lamin A, B1 and B2 "Half-minilamin" Dimers
Authors: Kapinos, Larisa E
Schumacher, Jens
Mücke, Norbert
Machaidze, Gia
Burkhard, Peter
Aebi, Ueli
Strelkov, Sergei
Herrmann, Harald # ×
Issue Date: Feb-2010
Publisher: Academic Press
Series Title: Journal of Molecular Biology vol:396 issue:3 pages:719-731
Abstract: Half-minilamins, representing amino- and carboxy-terminal fragments of human lamins A, B1 and B2 with a truncated central rod domain, were investigated for their ability to form distinct head-to-tail-type dimer complexes. This mode of interaction represents an essential step in the longitudinal assembly reaction exhibited by full-length lamin dimers. As determined by analytical ultracentrifugation, the amino-terminal fragments were soluble under low ionic strength conditions sedimenting with distinct profiles and s-values (1.6-1.8 S) indicating the formation of coiled-coil dimers. The smaller carboxy-terminal fragments were, except for lamin B2, largely insoluble under these conditions. However, after equimolar amounts of homotypic amino- and carboxy-terminal lamin fragments had been mixed in 4 M urea, upon subsequent renaturation the carboxy-terminal fragments were completely rescued from precipitation and distinct soluble complexes with higher s-values (2.3-2.7 S) were obtained. From this behavior, we conclude that the amino- and carboxy-terminal coiled-coil dimers interact to form distinct oligomers (i.e. tetramers). Furthermore, a corresponding interaction occurred also between heterotypic pairs of A- and B-type lamin fragments. Hence, A-type lamin dimers may interact with B-type lamin dimers head-to-tail to yield linear polymers. These findings indicate that a lamin dimer principally has the freedom for a "combinatorial" head-to-tail association with all types of lamins, a property that might be of significant importance for the assembly of the nuclear lamina. Furthermore, we suggest that the head-to-tail interaction of the rod end domains represents a principal step in the assembly of cytoplasmic intermediate filament proteins too.
ISSN: 0022-2836
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Biocrystallography
× corresponding author
# (joint) last author

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