%0 Journal Article %1 puetzNewInsightsMyosin2012a %A Puetz, Sandra %A Schroeter, Mechthild M. %A Piechura, Heike %A Reimann, Lena %A Hunger, Mona S. %A Lubomirov, Lubomir T. %A Metzler, Doris %A Warscheid, Bettina %A Pfitzer, Gabriele %C Netherlands %D 2012 %J Journal of muscle research and cell motility %K Animals,Male,Mice,Muscle Chains/*metabolism,Nucleotides Cyclic/*metabolism,Phosphorylation,to_read Light Relaxation,Muscle Smooth/*metabolism,Myosin %N 6 %P 471--483 %R 10.1007/s10974-012-9306-9 %T New Insights into Myosin Phosphorylation during Cyclic Nucleotide-Mediated Smooth Muscle Relaxation. %V 33 %X Nitrovasodilators and agonists, via an increase in intracellular cyclic nucleotide levels, can induce smooth muscle relaxation without a concomitant decrease in phosphorylation of the regulatory light chains (RLC) of myosin. However, since cyclic nucleotide-induced relaxation is associated with a decrease in intracellular Ca(2+), and hence, a decreased activity of MLCK, we tested the hypothesis that the site responsible for the elevated RLC phosphorylation is not Ser19. Smooth muscle strips from gastric fundus were isometrically contracted with ET-1 which induced an increase in monophosphorylation from 9~±~1~\% under resting conditions (PSS) to 36~±~1~\% determined with 2D-PAGE. Electric field stimulation induced a rapid, largely NO-mediated relaxation with a half time of 8~s, which was associated with an initial decline in RLC phosphorylation to 18~\% within 2~s and a rebound to 34~\% after 30~s whereas relaxation was sustained. In contrast, phosphorylation of RLC at Ser19 probed with phosphospecific antibodies declined in parallel with force. LC/MS and western blot analysis with phosphospecific antibodies against monophosphorylated Thr18 indicate that Thr18 is significantly monophosphorylated during sustained relaxation. We therefore suggest that (i) monophosphorylation of Thr18 rather than Ser19 is responsible for the phosphorylation rebound during sustained EFS-induced relaxation of mouse gastric fundus, and (ii) that relaxation can be ascribed to dephosphorylation of Ser19, the site considered to be responsible for regulation of smooth muscle tone.

@article{puetzNewInsightsMyosin2012a, abstract = {Nitrovasodilators and agonists, via an increase in intracellular cyclic nucleotide levels, can induce smooth muscle relaxation without a concomitant decrease in phosphorylation of the regulatory light chains (RLC) of myosin. However, since cyclic nucleotide-induced relaxation is associated with a decrease in intracellular [Ca(2+)], and hence, a decreased activity of MLCK, we tested the hypothesis that the site responsible for the elevated RLC phosphorylation is not Ser19. Smooth muscle strips from gastric fundus were isometrically contracted with ET-1 which induced an increase in monophosphorylation from 9~{\textpm}~1~\% under resting conditions (PSS) to 36~{\textpm}~1~\% determined with 2D-PAGE. Electric field stimulation induced a rapid, largely NO-mediated relaxation with a half time of 8~s, which was associated with an initial decline in RLC phosphorylation to 18~\% within 2~s and a rebound to 34~\% after 30~s whereas relaxation was sustained. In contrast, phosphorylation of RLC at Ser19 probed with phosphospecific antibodies declined in parallel with force. LC/MS and western blot analysis with phosphospecific antibodies against monophosphorylated Thr18 indicate that Thr18 is significantly monophosphorylated during sustained relaxation. We therefore suggest that (i) monophosphorylation of Thr18 rather than Ser19 is responsible for the phosphorylation rebound during sustained EFS-induced relaxation of mouse gastric fundus, and (ii) that relaxation can be ascribed to dephosphorylation of Ser19, the site considered to be responsible for regulation of smooth muscle tone.}, added-at = {2024-05-17T13:01:35.000+0200}, address = {Netherlands}, author = {Puetz, Sandra and Schroeter, Mechthild M. and Piechura, Heike and Reimann, Lena and Hunger, Mona S. and Lubomirov, Lubomir T. and Metzler, Doris and Warscheid, Bettina and Pfitzer, Gabriele}, biburl = {https://www.bibsonomy.org/bibtex/28b8ddac15b26b7f0528c4d941d52243a/warscheidlab}, doi = {10.1007/s10974-012-9306-9}, interhash = {2c2a8d182bb2e0fca6e1051d3c3c0178}, intrahash = {8b8ddac15b26b7f0528c4d941d52243a}, issn = {1573-2657 0142-4319}, journal = {Journal of muscle research and cell motility}, keywords = {Animals,Male,Mice,Muscle Chains/*metabolism,Nucleotides Cyclic/*metabolism,Phosphorylation,to_read Light Relaxation,Muscle Smooth/*metabolism,Myosin}, langid = {english}, month = dec, number = 6, pages = {471--483}, pmcid = {PMC3521644}, pmid = {22711245}, timestamp = {2024-05-17T13:01:35.000+0200}, title = {New Insights into Myosin Phosphorylation during Cyclic Nucleotide-Mediated Smooth Muscle Relaxation.}, volume = 33, year = 2012 }