LMNB1 and progeroid syndrome: We tested nine different tail constructs: lamin B1, lamin C, mature lamin A residues 385–646 (wildtype, S612A, T643A, or S612A/T643A), and prelamin A residues 385–664 bearing the progeria-associated Δ35, Δ50, or Δ90 deletions (Figure 2A).