Age-Related Decrease of Protein Kinase G Activation in Vascular Smooth Muscle Cells
| Autor: | Xiaowei Liu, Sylvia Chow, Richard Tu, Ching-Shwun Lin, Tom F. Lue |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Aging
medicine.medical_specialty Vascular smooth muscle Phosphodiesterase 3 Biophysics Stimulation Biology Biochemistry Muscle Smooth Vascular Cyclic nucleotide chemistry.chemical_compound Internal medicine Cyclic AMP Cyclic GMP-Dependent Protein Kinases medicine Animals Humans Phosphorylation Protein kinase A Cyclic GMP Molecular Biology Aorta Cells Cultured Microfilament Proteins Haplorhini Cell Biology Phosphoproteins Rats Enzyme Activation Endocrinology chemistry Phosphoprotein COS Cells cardiovascular system PDE10A Cell Adhesion Molecules cGMP-dependent protein kinase |
| Zdroj: | Biochemical and Biophysical Research Communications. 287:244-248 |
| ISSN: | 0006-291X |
| DOI: | 10.1006/bbrc.2001.5567 |
| Popis: | Protein kinase G-I (PKG-I) activation is essential for vascular relaxation; however, its quantitative analysis in intact cells has been difficult. To overcome this difficulty, a monoclonal antibody, VASP-16C2, was recently developed that detects phosphorylated serine residue 239 of vasodilator-stimulated phosphoprotein (VASP), a substrate of PKG-I. In this study, we used this antibody to examine (i) possible functional differences between the alpha and beta isoforms of PKG-I, (ii) ability of cAMP to activate PKG-I, as compared to cGMP, the principal PKG-I-activating cyclic nucleotide, and (iii) time course and levels of PKG-I activation in vascular smooth muscle cells (VSMC) of young and old rats. We created COS-7 cell clones that overexpressed PKG-Ialpha or PKG-Ibeta, treated them with cAMP or cGMP, and analyzed their cell lysates for reactivity with VASP-16C2. The results showed that PKG-Ialpha phosphorylated VASP at a higher level than PKG-Ibeta, and cAMP was slightly weaker than cGMP in PKG-I activation. VSMC of young rats responded to cAMP or cGMP stimulation in a dose-dependent manner with increasing levels of PKG-I activation. The response was detected within 10 min and continued for at least 24 h. In contrast, VSMC of old rats showed no PKG-I activation during the first hour of cAMP or cGMP stimulation and, at 24 h these cells showed only low-level PKG-I activation. We propose that the reduced PKG-I activation may explain why vascular relaxation is decreased in older individuals. |
| Databáze: | OpenAIRE |
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