The small heat shock-related protein, HSP20, is phosphorylated on serine 16 during cyclic nucleotide-dependent relaxation

Arthur Beall, Drew Bagwell, David Woodrum, Terrence A. Stoming, Kanefusa Kato, Atsushi Suzuki, Howard Rasmussen, Colleen M. Brophy

Research output: Contribution to journalArticlepeer-review

118 Scopus citations

Abstract

The small heat shock-related protein 20 (HSP20) is present in four isoforms in bovine carotid artery smooth muscles. Three of the isoforms are phosphorylated and one is not. Increases in the phosphorylation of two isoforms of HSP20 (isoform 3, pI 5.9; and 8, pI 5.7) are associated with cyclic nucleotide-dependent relaxation of bovine carotid artery smooth muscles. Increases in the phosphorylation of another isoform (isoform 4, pI 6.0) are associated with phorbol ester-induced contraction of bovine carotid artery smooth muscles. In this investigation we determined that isoforms 3 and 8 are phosphorylated on Ser16 of the HSP20 molecule during activation of cAMP-dependent signaling pathways. Phosphorylation state-specific antibodies produced against a peptide containing phosphorylated Ser16 recognized isoforms 3 and 8 but not isoform 4. In human vascular tissue, only isoform 3 is present. Incubation of transiently permeabilized strips of bovine carotid artery smooth muscle with synthetic peptides in which Ser16 is phosphorylated, inhibits contractile responses to high extracellular KCl and to serotonin. These data suggest that phosphorylation of HSP20 on Ser16 modulates cAMP-dependent vasorelaxation.

Original languageEnglish (US)
Pages (from-to)11344-11351
Number of pages8
JournalJournal of Biological Chemistry
Volume274
Issue number16
DOIs
StatePublished - Apr 16 1999

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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