Figure 2
Identification of CDK1-catalyzed phosphorylation site(s) on lamin A/C as P-STM phosphoepitope(s). (A) A schematic diagram of full-length lamin C (aa 1–572) and different truncated forms (N, N1, N2, and C) of GST-lamin C. (B) The four purified GST-lamin C recombinant proteins (1.5 μg) were in vitro-phosphorylated by CDK1 in the presence of [γ-32P]-ATP. Reaction products were resolved by SDS-PAGE on 10% gels and visualized by Coomassie Blue staining (upper panel), followed by autoradiography (middle panel) or immunoblotting with P-STM antibody (lower panel). (C) A schematic diagram of GST-lamin C-N1 mutants. Mutants were generated by site-directed mutagenesis to replace Thr-19, Ser-22, or Thr-19/Ser-22 with Ala. (D) The four purified GST-lamin C-N1 fusion proteins (1.5 μg) were phosphorylated by CDK1 and processed as described above.