Nuclear export signal in CDC25B

• Published in: Biochemical and biophysical research communications Vol. 316; no. 1; pp. 226 - 232
• Main Authors: Uchida, Sanae, Ohtsubo, Motoaki, Shimura, Mari, Hirata, Masato, Nakagama, Hitoshi, Matsunaga, Tsukasa, Yoshida, Minoru, Ishizaka, Yukihito, Yamashita, Katsumi
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 26.03.2004
• Subjects: 14-3-3; Active Transport, Cell Nucleus; Amino Acid Sequence; cdc25 Phosphatases - analysis; cdc25 Phosphatases - chemistry; cdc25 Phosphatases - genetics; CDC25B; Cell Cycle Proteins - analysis; Cell Cycle Proteins - chemistry; Cell Cycle Proteins - genetics; Cell Nucleus - chemistry; Cell Nucleus - metabolism; Cytoplasm - chemistry; Fatty Acids, Unsaturated - pharmacology; GFP; Humans; Hydrophobic and Hydrophilic Interactions; Leptomycin B; Molecular Sequence Data; Mutation; Nuclear export signal; Protein Sorting Signals; Subcellular localization; GFP; 14-3-3; Subcellular localization; CDC25B; Nuclear export signal; Leptomycin B
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2004.02.039

CDC25B is a dual-specificity phosphatase that activates CDK1/cyclin B. The nuclear exclusion of CDC25B is controlled by the binding of 14-3-3 to the nuclear export signal (NES) of CDC25B, which was reported to be amino acids H28 to L40 in the N-terminal region of CDC25B. In studying the subcellular localization of CDC25B, we found a functional NES at V52 to L65, the sequence of which is VTT LTQT MHD LAG L, where bold letters are leucine or hydrophobic amino acids frequently seen in an NES. The deletion of this NES sequence caused the mutant protein to locate exclusively in nuclei, while NES-fused GFP was detected in the cytoplasm. Moreover, the introduction of point mutations at some of the critical amino acids impaired cytoplasmic localization. Treatment with leptomycin B, a potent inhibitor of CRM1/exportin1, disrupted the cytoplasmic localization of both Flag-tagged CDC25B and NES-fused GFP. From these results, we concluded that the sequence we found is a bona fide NES of CDC25B.