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PKC and PKA phosphorylation affect the subcellular localization of claudin-1 in melanoma cells.
- Source :
-
International journal of medical sciences [Int J Med Sci] 2009; Vol. 6 (2), pp. 93-101. Date of Electronic Publication: 2009 Mar 12. - Publication Year :
- 2009
-
Abstract
- Cytoplasmic expression of claudin-1 in metastatic melanoma cells correlates to increased migration, and increased secretion of MMP-2 in a PKC dependent manner, whereas claudin-1 nuclear expression is found in benign nevi. Melanoma cells were transfected with a vector expressing CLDN-1 fused to a nuclear localization signal (NLS). Despite significant nuclear localization of claudin-1, there was still transport of claudin-1 to the cytoplasm. Phorbol ester treatment of cells transfected with NLS-claudin-1 resulted in an exclusion of claudin-1 from the nucleus, despite the NLS. To ascertain whether PKC or PKA were involved in this translocation, we mutated the putative phosphorylation sites within the protein. We found that mutating the PKC phosphorylation sites to mimic a non-phosphorylated state did not cause a shift of claudin-1 to the nucleus of the cells, but mutating the PKA sites did. Mutations of either site to mimic constitutive phosphorylation resulted in cytoplasmic claudin-1 expression. Stable claudin-1 transfectants containing non-phosphorylatable PKA sites exhibited decreased motility. These data imply that subcellular localization of claudin-1 can be controlled by phosphorylation, dicating effects on metastatic capacity.
- Subjects :
- Biological Transport genetics
Cell Line, Tumor
Cell Nucleus drug effects
Cell Nucleus genetics
Cell Nucleus metabolism
Claudin-1
Computer Simulation
Cytoplasm genetics
Cytoplasm metabolism
Enzyme Activation
Genetic Vectors
Humans
Immunohistochemistry
Matrix Metalloproteinase 2 metabolism
Melanoma metabolism
Mutagenesis, Site-Directed
Neoplasm Invasiveness
Neoplasm Metastasis
Nuclear Localization Signals genetics
Nuclear Localization Signals metabolism
Phosphorylation
Subcellular Fractions metabolism
Tetradecanoylphorbol Acetate pharmacology
Transfection
Cyclic AMP-Dependent Protein Kinases metabolism
Melanoma pathology
Membrane Proteins metabolism
Protein Kinase C metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1449-1907
- Volume :
- 6
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- International journal of medical sciences
- Publication Type :
- Academic Journal
- Accession number :
- 19305641
- Full Text :
- https://doi.org/10.7150/ijms.6.93