biostudies-literatureUnknownWang ZNIGMS NIH HHSProteins with nuclear localization sequences (NLSs) are directed into the cell nucleus through interactions between the NLS and importin proteins. NLSs are generally short motifs rich in basic amino acids; however, identifying NLSs can be challenging due to the lack of a universally conserved sequence. In this study, we characterized the sequence specificity of an essential and conserved NLS in Mcm3, a subunit of the replicative DNA helicase. Through mutagenesis and AlphaFold 3 (AF3) modeling, we demonstrate that the precise positioning of basic residues within the NLS is critical for nuclear transport of Mcm3 through optimal interactions with importin. Disrupting these interactions impairs the nuclear import of Mcm3, resulting in defective chromatin loading of MCM and poor cell growth. OubioRxiv : the preprint server for biology2024.11.14.623588https://www.ebi.ac.uk/biostudies/studies/S-EPMC11601334biostudies-literatureSequence specificity of an essential nuclear localization sequence in Mcm3.PMC11601334R01 GM116897R01 GM151191Zhang YJSuhandynata RTBilsborrow KLeslie MZhang QYWang ZZhou HfalseSequence specificity of an essential nuclear localization sequence in Mcm3.Proteins with nuclear localization sequences (NLSs) are directed into the cell nucleus through interactions between the NLS and importin proteins. NLSs are generally short motifs rich in basic amino acids; however, identifying NLSs can be challenging due to the lack of a universally conserved sequence. In this study, we characterized the sequence specificity of an essential and conserved NLS in Mcm3, a subunit of the replicative DNA helicase. Through mutagenesis and AlphaFold 3 (AF3) modeling, we demonstrate that the precise positioning of basic residues within the NLS is critical for nuclear transport of Mcm3 through optimal interactions with importin. Disrupting these interactions impairs the nuclear import of Mcm3, resulting in defective chromatin loading of MCM and poor cell growth. Ou2024-01-01T00:00:00Z2024 Nov2025-04-04T01:20:08.563Z2025-04-04T01:20:08.563ZS-EPMC116013343960561410.1101/2024.11.14.623588