Anti-Importin a 3

1. Supplementary figure 1 A B Primary hippocampal neurons Primary hippocampal neurons D E Primary hippocampal neurons Primary hippocampal neurons Mouse ES cells Mouse ES cells NIH3T3 cells NIH3T3 cells Mouse ES cells Mouse ES cells NIH3T3 cells NIH3T3 cells C Primary hippocampal neurons * F * * Primary hippocampal neurons * Mouse ES cells NIH3T3 cells Mouse ES cells NIH3T3 cells * Anti-NeuroD1 Anti-GAPDH Anti-Importin a1 Anti-E47 Anti-Importin b1 Anti-Importin a3

2. Supplementary figure 2 Flag-NeuroD1 Flag-D134-161 Anti-flag DAPI

3. Supplementary figure 3 GFP Injection Marker GFP Injection Marker B E F A NeuroD1-GFP C D G H NeuroD1-GFP + RanQ69L-GTP NIH3T3 HeLa

4. Supplementary figure 4 B A NeuroD1-GST +cytosol +RanQ69L－GTP NeuroD1-GST +cytosol +RanQ69L－GTP NeuroD1-GST +cytosol NeuroD1-GST +cytosol GST beads+Cytosol Hela cell lysate GST beads+Cytosol Hela cell lysate 150 100 75 Anti-RanBP5 Anti-RanBP7

5. Supplementary figure 5 Importin a + b1 Importin b1 (NeuroD1)

6. (A) Supplementary figure 6 (B) Database : NCBInr 20100904 (11744690 sequences; 4010973687 residues) Taxonomy : Homo sapiens (human) (232987 sequences) Timestamp : 8 Sep 2010 at 09:45:05 GMT Top Score : 182 for gi|19923142, importin subunit beta-1 [Homo sapiens] Mascot Score Histogram Protein score is -10*Log(P), where P is the probability that the observed match is a random event. Protein scores greater than 66 are significant (p<0.05) Search Parameters Enzyme : Trypsin Fixed modifications : Carbamidomethyl (C) Variable modifications : Oxidation (M) Mass values : Monoisotopic Protein Mass : 95 kDa Peptide Mass Tolerance : ± 0.2 Da Peptide Charge State : 1+ Max Missed Cleavages : 1 Number of queries : 36