Transduction of biologically active motifs of the small heat shock-related protein HSP20 leads to relaxation of vascular smooth muscle.

Flynn CR, Komalavilas P, Tessier D, Thresher J, Niederkofler EE, Dreiza CM, Nelson RW, Panitch A, Joshi L, Brophy CM
FASEB J. 2003 17 (10): 1358-60

PMID: 12738803 · DOI:10.1096/fj.02-1028fje

Activation of cyclic nucleotide-dependent signaling pathways leads to phosphorylation of the small heat shock-related protein, HSP20, on serine 16, and relaxation of vascular smooth muscle. In this study, we used an enhanced protein transduction domain (PTD) sequence to deliver HSP20 phosphopeptide analogs into porcine coronary artery. The transduction of phosphoHSP20 analogs led to dose-dependent relaxation of coronary artery smooth muscle. Peptides containing the protein transduction domain coupled to a random orientation of the same amino acids did not. Direct fluorescence microscopy of arterial rings incubated with fluorescein isothiocyanate (FITC)-PTD or FITC-PTD-HSP20 peptides showed a diffuse peptide uptake. Mass spectrometric immunoassays (MSIAs) of smooth muscle homogenates were used to determine whether the phosphopeptide analogs affected the phosphorylation of endogenous HSP20. Treatment with the phosphodiesterase inhibitor papaverine led to a mass shift of 80 Da. However, there was no mass shift of HSP20 in muscles treated with phosphoHSP20 analogs. This suggests that the PTD-phosphoHSP20 peptide alone is sufficient to inhibit force maintenance and likely has a direct effect on the target of phosphorylated HSP20. These results suggest that transduction of phosphopeptide analogs of HSP20 directly alters physiological responses of intact muscles. The data also support a direct role for phosphorylated HSP20 in mediating vasorelaxation.

MeSH Terms (21)

Amino Acid Motifs Animals Cell Line Culture Techniques Heat-Shock Proteins HSP20 Heat-Shock Proteins Models, Biological Muscle, Smooth, Vascular Myocardium Nucleotides, Cyclic Papaverine Phosphodiesterase Inhibitors Phosphopeptides Phosphoproteins Phosphorylation Rabbits Serotonin Swine Transduction, Genetic Vasoconstriction Vasodilation

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