Identification of a C-terminal region that is required for the nuclear translocation of ERK2 by passive diffusion.
Extracellular signal-regulated kinase 2 (ERK2) is located in the cytoplasm of resting cells and translocates into the nucleus upon extracellular stimuli by active transport of a dimer. Passive transport of an ERK2 monomer through the nuclear pore is also reported to coexist. We attempted to characterize the cytoplasmic retention and nuclear translocation of fusion proteins between deletion and site-directed mutants of ERK2 and green fluorescent protein (GFP). The overexpressed ERK2-GFP fusion protein is usually localized to both the cytoplasm and the nucleus unless a cytoplasmic anchoring protein is coexpressed. Deletion of 45 residues, but not 43 residues, from the C terminus of ERK2 prevented the nuclear distribution of the ERK2-GFP fusion protein. Substitution of a part of residues 299-313 to alanine residues also prevented the nuclear distribution of the ERK2-GFP fusion protein without abrogation of its nuclear active transport. These observations may indicate that the passive diffusion of ERK2 into the nucleus is not simple diffusion but includes a specific interaction process between residues 299-313 and the nuclear pore complex and that this interaction is not required for the active transport. We also showed that substitution of Tyr(314) to alanine residue abrogated the cytoplasmic retention of the ERK2-GFP fusion protein by PTP-SL but not by MEK1.
Shibayama
Sotaro
S
Department of Biochemistry I, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
Shibata-Seita
Ryoko
R
Miura
Kenji
K
Kirino
Yutaka
Y
Takishima
Kunio
K
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D019943:Amino Acid Substitution; D000818:Animals; D003593:Cytoplasm / Q000378:metabolism; D004058:Diffusion; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D016296:Mutagenesis; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017384:Sequence Deletion; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D019950:Mitogen-Activated Protein Kinase 1; D013755:Tetradecanoylphorbol Acetate