Fig. 8.

A possible role of the far C-terminal region of lamin A in determining subcellular localization is revealed by analysis of triple mutations. Phospho-mimetic substitutions of residues S22, S392 and S628 show that all three sites combined have a substantial effect on the distribution of GFP–lamin A. The distributions of the triple mutants GFP–lamin A S22D S392D S628D and S22D S392D S628A were determined by using confocal fluorescence microscopy (lamin A distribution is shown in green). DNA was labeled with Hoechst 33258 [shown in white, or blue in the overlay (OL)]. The distribution of the S22D S392D S628A triple mutant was indistinguishable from that of the S22D S392D double mutant, whereas the GFP–lamin A S22D S392D S628D triple mutant showed variable degrees of localization to the cytoplasm (arrow heads), as well as a prominent nucleoplasmic distribution. Scale bars: 10 µm.