A caldesmon peptide activates smooth muscle via a mechanism similar to ERK-mediated phosphorylation.
Caldesmon (CaD) is thought to regulate smooth muscle contraction, because it binds actin and inhibits actomyosin interactions. A synthetic actin-binding peptide (GS17C) corresponding to Gly666-Ser682 of chicken gizzard CaD has been shown to induce force development in permeabilized smooth muscle cells. The mechanism of GS17C's action remains unclear, although a structural effect was postulated. By photo-crosslinking and fluorescence quenching experiments with a gizzard CaD fragment (H32K; Met563-Pro771) and its mutants, we showed that GS17C indeed dissociated the C-terminal region of H32K from actin, in a manner similar to extracellular signal-regulated kinase-mediated phosphorylation, thereby reversing the CaD-imposed inhibition and enabling the actomyosin interaction.
Huang
Renjian
R
Boston Biomedical Research Institute, Muscle and Motility Group, 64 Grove St., Watertown, MA 02472, USA.
Wang
C-L Albert
CL
D000205:Actomyosin / Q000737:chemistry / Q000378:metabolism; D019943:Amino Acid Substitution; D000818:Animals; D002148:Calmodulin-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002645:Chickens / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000737:chemistry* / Q000378:metabolism; D005895:Gizzard, Avian / Q000737:chemistry* / Q000378:metabolism; D009119:Muscle Contraction / Q000502:physiology; D009130:Muscle, Smooth / Q000737:chemistry* / Q000378:metabolism; D010455:Peptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D017354:Point Mutation; D011485:Protein Binding; D011817:Rabbits
D002148:Calmodulin-Binding Proteins; D010455:Peptides; D000205:Actomyosin; D048049:Extracellular Signal-Regulated MAP Kinases