Mutational analysis of the role of a putative NES and a lysine within the NLS_bp in nuclear export of <i>Paramyxovirinae</i> matrix proteins.

<p><b>(A)</b> Alignment of <i>Paramyxovirinae</i> M sequence motifs that correspond to NiV-M's leucine-rich NES and NLS_bp, which contains a putative ubiquitinated lysine. Predicted critical residues are colored blue. Residues mutated in this study are also underlined in bold font. <b>(B-G)</b> Extended Focus (maximum intensity projection) views of 3D confocal micrographs of HeLa cells transfected with WT, or the indicated mutant GFP-tagged <b>(B)</b> NiV-M, <b>(C)</b> HeV-M, <b>(D)</b> SeV-M, <b>(E)</b> MuV-M, <b>(F)</b> NDV-M or <b>(G)</b> MeV-M. Cells were counterstained with DAPI to visualize nuclear DNA, blue, and fluorescent phalloidin to visualize the F-actin cytoskeleton, red. Scale bar 10 μm. <b>(H)</b> The amount of nuclear M fluorescence per cell was quantified from 3D reconstructed confocal micrographs. *p<0.05; **p<0.01; ***p<0.001; ****p<0.0001; NS, not significant by one-way ANOVA with Bonferroni adjustment for multiple comparisons.