Nuclear localization signal in a cancer-related transcriptional regulator protein NAC1.
Nucleus accumbens-associated protein 1 (NAC1) might have potential oncogenic properties and participate in regulatory networks for pluripotency. Although NAC1 is described as a transcriptional regulator, the nuclear import machinery of NAC1 remains unclear. We found, using a point mutant, that dimer formation was not committed to the nuclear localization of NAC1 and, using deletion mutants, that the amino-terminal half of NAC1 harbored a potential nuclear localization signal (NLS). Wild type, but not mutants of this region, alone was sufficient to drive the importation of green fluorescent protein (GFP) into the nucleus. Bimax1, a synthetic peptide that blocks the importin α/β pathway, impaired nuclear localization of NAC1 in cells. We also used the binding properties of importin to demonstrate that this region is an NLS. Furthermore, the transcriptional regulator function of NAC1 was dependent on its nuclear localization activity in cells. Taken together, these results show that the region with a bipartite motif constitutes a functional nuclear import sequence in NAC1 that is independent of NAC1 dimer formation. The identification of an NAC1 NLS thus clarifies the mechanism through which NAC1 translocates to the nucleus to regulate the transcription of genes involved in oncogenicity and pluripotency.
Department of Biochemistry, Shimane University School of Medicine, Izumo, Japan. .
Kosuke
K
Okazaki
Naomi
N
Nakayama
Yuko
Y
Nariai
Kentaro
K
Nakayama
Kohji
K
Miyazaki
Riruke
R
Maruyama
Hiroaki
H
Kato
Shunichi
S
Kosugi
Takeshi
T
Urano
Gyosuke
G
Sakashita
D021581:Active Transport, Cell Nucleus / Q000502:physiology; D019281:Dimerization; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D028884:Karyopherins / Q000378:metabolism; D009154:Mutation; D009363:Neoplasm Proteins / Q000737:chemistry*; D009369:Neoplasms / Q000378:metabolism; D019913:Nuclear Localization Signals / Q000032:analysis* / Q000378:metabolism; D011485:Protein Binding; D012097:Repressor Proteins / Q000737:chemistry*
D028884:Karyopherins; C516477:NACC1 protein, human; D009363:Neoplasm Proteins; D019913:Nuclear Localization Signals; D012097:Repressor Proteins; D049452:Green Fluorescent Proteins