Protein kinase B phosphorylates AHNAK and regulates its subcellular localization

Citation
J. Sussman et al., Protein kinase B phosphorylates AHNAK and regulates its subcellular localization, J CELL BIOL, 154(5), 2001, pp. 1019-1030
Citations number
52
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Cell & Developmental Biology
Journal title
JOURNAL OF CELL BIOLOGY
ISSN journal
0021-9525 → ACNP
Volume
154
Issue
5
Year of publication
2001
Pages
1019 - 1030
Database
ISI
SICI code
0021-9525(20010903)154:5<1019:PKBPAA>2.0.ZU;2-7
Abstract
AHNAK is a ubiquitously expressed giant phosphoprotein that was initially i dentified as a gene product subject to transcriptional repression in neurob lastoma. AHNAK is predominantly nuclear in cells of nonepithelial origin, b ut is cytoplasmic or associated with plasma membrane in epithelial cells. I n this study we show that the extranuclear localization of AHNAK in epithel ial cells depends on the formation of cell-cell contacts. We show that AHNA K is a phosphorylation substrate of protein kinase B (PKB) in vitro and in vivo. Nuclear exclusion of AHNAK is mediated through a nuclear export signa l (NES) in a manner that depends on the phosphorylation of serine 5535 of A HNAK by PKB, a process that also plays a major role in determining extranuc lear localization of AHNAK. AHNAK is a new PKB substrate whose function, th ough unknown, is likely to be regulated by its localization, which is in tu rn regulated by PKB.