title: The nuclear localization of glycogen synthase kinase 3β is required its putative PY-nuclear localization sequences.
abstract: Glycogen synthase kinase-3β(GSK-3β), which is a member of the serine/threonine kinase family, has been shown to be crucial for cellular survival, differentiation, and metabolism. Here, we present evidence that GSK-3β is associated with the karyopherin β2 (Kap β2) (102-kDa), which functions as a substrate for transportation into the nucleus. A potential PY-NLS motif ((109)IVRLRYFFY(117)) was observed, which is similar with the consensus PY NLS motif (R/K/H)X(2-5)PY in the GSK-3β catalytic domain. Using a pull down approach, we observed that GSK-3β physically interacts with Kap β2 both in vivo and in vitro. Secondly, GSK-3β and Kap β2 were shown to be co-localized by confocal microscopy. The localization of GSK-3β to the nuclear region was disrupted by putative Kap β2 binding site mutation. Furthermore, in transient transfection assays, the Kap β2 binding site mutant induced a substantial reduction in the in vivo serine/threonine phosphorylation of GSK-3β, where- as the GSK-3β wild type did not. Thus, our observations indicated that Kap β2 imports GSK-3β through its putative PY NLS motif from the cytoplasm to the nucleus and increases its kinase activity.
authors.affiliation: Department of Biology Education, Chungbuk National University, Cheongju 361-763, Korea.
authors.forename: Sung Hwa
authors.initials: SH
authors.lastname: Shin
authors.forename: Eun Jeoung
authors.initials: EJ
authors.lastname: Lee
authors.forename: Jaesun
authors.initials: J
authors.lastname: Chun
authors.forename: Sunghee
authors.initials: S
authors.lastname: Hyun
authors.forename: Youg Il
authors.initials: YI
authors.lastname: Kim
authors.forename: Sang Sun
authors.initials: SS
authors.lastname: Kang
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000201:enzymology*; D002470:Cell Survival; D004795:Enzyme Stability; D038362:Glycogen Synthase Kinase 3 / Q000737:chemistry* / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D019913:Nuclear Localization Signals / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D013329:Structure-Activity Relationship; D013347:Subcellular Fractions / Q000201:enzymology; D028961:beta Karyopherins / Q000378:metabolism
chemical_list: D050505:Mutant Proteins; D019913:Nuclear Localization Signals; D028961:beta Karyopherins; D010768:Phosphoserine; D019000:Phosphotyrosine; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3