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Sequence requirement for nuclear localization and growth inhibition of p27 Kip1R , a degradation‐resistant isoform of p27 Kip1
Author(s) -
Hirano Katsuya,
Zeng Ying,
Hirano Mayumi,
Nishimura Junji,
Kanaide Hideo
Publication year - 2003
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.10499
Subject(s) - nuclear localization sequence , nuclear export signal , nuclear protein , cytoplasm , nls , cell cycle , cell nucleus , gene isoform , subcellular localization , nuclear transport , amino acid , biology , cyclin , mutant , cell growth , biochemistry , kinase , microbiology and biotechnology , cell , gene , transcription factor
Abstract p27 Kip1R is an isoform of p27 Kip1 , having a distinct C‐terminus. The sequences of p27 Kip1R required for nuclear localization and growth inhibition were determined in HeLa cells using a green fluorescence protein (GFP) as a reporter molecule. Region 153–168 and residues K168 and I169 were determined to play a critical role in the nuclear localization of p27 Kip1R . Aliphatic amino acid was found to be a substitute for the basic residue in the typical nuclear localization signal, while its functional substitution was incomplete, thereby causing a significant cytoplasmic retention of p27 Kip1R . p27 Kip1R is thus the first example of an atypical bipartite nuclear localization signal with aliphatic amino acid as a functional residue. Despite cytoplasmic retention, p27 Kip1R inhibited the cell growth as well as p27 Kip1 , while GFP alone had no effect. The mutants lacking an N‐terminus containing the binding regions for cyclins and cyclin‐dependent kinases also showed a significant degree of nuclear localization, but failed to inhibit cell growth. The growth inhibition by p27 Kip1R as well as p27 Kip1 was thus suggested to originate in the common N‐terminal region. J. Cell. Biochem. 89: 191–202, 2003. © 2003 Wiley‐Liss, Inc.