title: IGF-I regulated phosphorylation and translocation of PDK-1 in neurons.
abstract: 3'-phosphoinositide-dependent protein kinase-1 (PDK-1) is a crucial serine/threonine kinase in the insulin-like growth factor-I (IGF-I)/AKT signaling pathway, but its function and localization in the nervous system has not been fully characterized. In this study, we compared the localization of PDK-1 in adult neurons and non-neuronal PC-3 cells. We showed that PC-3 cells expressed phosphorylated and nonphosphorylated PDK-1 in the cytoplasm and nucleoplasm. In contrast, neuronal PDK-1 was located in the nucleoplasm and the phosphorylated form was located along the perinuclear region. Furthermore, we found that IGF-I transiently increased phosphorylation of neuronal PDK-1, resulting in its translocation to other cellular compartments. Our findings suggest that IGF-I may regulate neuronal PDK-1 differently than in non-neuronal cells, which may indicate a novel role for PDK-1 in IGF-I-mediated neuroprotective signaling.
authors.affiliation: Department of Neurosurgery, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA.
authors.forename: Betty B
authors.initials: BB
authors.lastname: Alajajian
authors.forename: Lauren
authors.initials: L
authors.lastname: Fletcher
authors.forename: Elif
authors.initials: E
authors.lastname: Isgor
authors.forename: David F
authors.initials: DF
authors.lastname: Jimenez
authors.forename: Murat
authors.initials: M
authors.lastname: Digicaylioglu
mesh_terms: D064413:3-Phosphoinositide-Dependent Protein Kinases; D000818:Animals; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D007334:Insulin-Like Growth Factor I; D064413:3-Phosphoinositide-Dependent Protein Kinases; C578562:PDPK1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt