Phosphorylation at the Nuclear Localization Signal of Ca2+/Calmodulin-dependent Protein Kinase II Blocks Its Nuclear Targeting

Translocation of protein kinases with broad substrate specificities between different subcellular compartments by activation of signaling pathways is an established mechanism to direct the activity of these enzymes toward particular substrates. Recently, we identified two isoforms of Ca2+/calmodulin...

Full description

Saved in:
Bibliographic Details
Published in:The Journal of biological chemistry 1998-07, Vol.273 (31), p.19763-19771
Main Authors: Heist, E. Kevin, Srinivasan, Mallika, Schulman, Howard
Format: Article
Language:English
Subjects:
Amino Acid Sequence
Animals
Binding Sites - genetics
Calcium - metabolism
Calcium-Calmodulin-Dependent Protein Kinase Type 1
Calcium-Calmodulin-Dependent Protein Kinase Type 2
Calcium-Calmodulin-Dependent Protein Kinase Type 4
Calcium-Calmodulin-Dependent Protein Kinases - chemistry
Calcium-Calmodulin-Dependent Protein Kinases - genetics
Calcium-Calmodulin-Dependent Protein Kinases - metabolism
COS Cells
Fluorescent Antibody Technique
Immunohistochemistry
Molecular Sequence Data
Mutagenesis, Site-Directed - genetics
Mutation
Nuclear Localization Signals - physiology
Phosphorylation
Receptors, Cytoplasmic and Nuclear - metabolism
Serine - metabolism
Transfection - genetics
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Translocation of protein kinases with broad substrate specificities between different subcellular compartments by activation of signaling pathways is an established mechanism to direct the activity of these enzymes toward particular substrates. Recently, we identified two isoforms of Ca2+/calmodulin-dependent protein kinase II (CaM kinase II), which are targeted to the nucleus by an alternatively spliced nuclear localization signal (NLS). Here we report that cotransfection with constitutively active mutants of CaM kinase I or CaM kinase IV specifically blocks nuclear targeting of CaM kinase II as a result of phosphorylation of a Ser immediately adjacent to the NLS of CaM kinase II. Both CaM kinase I and CaM kinase IV are able to phosphorylate this Ser residue in vitro, and mutagenesis studies suggest that this phosphorylation is both necessary and sufficient to block nuclear targeting. Furthermore, we provide experimental evidence that introduction of a negatively charged residue at this phosphorylation site reduces binding of the kinase to an NLS receptor in vitro, thus providing a mechanism that may explain the blockade of nuclear targeting that we have observedin situ.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.273.31.19763