Live-Cell Fluorescence Imaging Reveals the Dynamics of Protein Kinase CK2 Individual Subunits
AUTOR(ES)
Filhol, Odile
FONTE
American Society for Microbiology
RESUMO
Protein kinase CK2 is a multifunctional enzyme which has long been described as a stable heterotetrameric complex resulting from the association of two catalytic (α or α′) and two regulatory (β) subunits. To track the spatiotemporal dynamics of CK2 in living cells, we fused its catalytic α and regulatory β subunits with green fluorescent protein (GFP). Both CK2 subunits contain nuclear localization domains that target them independently to the nucleus. Imaging of stable cell lines expressing low levels of GFP-CK2α or GFP-CK2β revealed the existence of CK2 subunit subpopulations exhibiting differential dynamics. Once in the nucleus, they diffuse randomly at different rates. Unlike CK2β, CK2α can shuttle, showing the dynamic nature of the nucleocytoplasmic trafficking of the kinase. When microinjected in the cytoplasm, the isolated CK2 subunits are rapidly translocated into the nucleus, whereas the holoenzyme complex remains in this cell compartment, suggesting an intramolecular masking of the nuclear localization sequences that suppresses nuclear accumulation. However, binding of FGF-2 to the holoenzyme triggers its nuclear translocation. Since the substrate specificity of CK2α is dramatically changed by its association with CK2β, the control of the nucleocytoplasmic distribution of each subunit may represent a unique potential regulatory mechanism for CK2 activity.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=140707Documentos Relacionados
- Live-cell imaging reveals divergent intracellular dynamics of polyglutamine disease proteins and supports a sequestration model of pathogenesis
- Live-Cell Analysis of a Green Fluorescent Protein-Tagged Herpes Simplex Virus Infection
- Crystal structure of human protein kinase CK2: insights into basic properties of the CK2 holoenzyme
- Protein kinase CK2 and protein kinase D are associated with the COP9 signalosome
- The protein kinase CK2 is involved in regulation of circadian rhythms in Arabidopsis