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Polyamines inhibit ...
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Swärd, KarlLund University,Lunds universitet,Kärlfysiologi,Forskargrupper vid Lunds universitet,Vascular Physiology,Lund University Research Groups
(author)
Polyamines inhibit myosin phosphatase and increase LC20 phosphorylation and force in smooth muscle
- Article/chapterEnglish1995
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LIBRIS-ID:oai:lup.lub.lu.se:a318afe9-3167-40d9-9a17-81d8381f4c66
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https://lup.lub.lu.se/record/1109022URI
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Language:English
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Summary in:English
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Subject category:art swepub-publicationtype
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Subject category:ref swepub-contenttype
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The increase in Ca(2+)-activated force caused by polyamines in beta-escin-permeabilized guinda pig ileum is shown to be associated with increased myosin 20-kDa light chain (LC20) phosphorylation and shortening velocity. Myosin LC20 dephosphorylation with arrested kinase activity was slower in the presence of 1 mM spermine. Smooth muscle phosphatases (SMP-I, -II, -III, and -IV) isolated from turkey gizzard are all active against phosphorylated LC20, but only SMP-III and -IV dephosphorylate heavy meromyosin (HMM). Spermine inhibited SMP-III activity toward LC20 but stimulated HMM dephosphorylation, whereas SMP-IV was inhibited with both substrates. In contrast, SMP-I and -II were stimulated by spermine. The relative effects of different polyamines correlated with an increasing number of positive charges. Spermine did not affect binding of SMP-IV to myosin and did not dissociate any of the subunits of the enzyme. Incubation of permeabilized strips with SMP-IV resulted in attenuated responses to Ca2+, an effect that was opposed by spermine and abolished by microcystin-LR. We conclude that spermine selectively inhibits myosin phosphatase activity and suggest that polyamines function as endogenous myosin phosphatase inhibitors.
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Pato, M DUniversity of Saskatchewan
(author)
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Nilsson, Bengt-OlofLund University,Lunds universitet,Kärlfysiologi,Forskargrupper vid Lunds universitet,Vascular Physiology,Lund University Research Groups(Swepub:lu)mphy-bon
(author)
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Nordström, InaLund University,Lunds universitet,Kärlfysiologi,Forskargrupper vid Lunds universitet,Vascular Physiology,Lund University Research Groups(Swepub:lu)mphy-ino
(author)
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Hellstrand, PerLund University,Lunds universitet,Kärlfysiologi,Forskargrupper vid Lunds universitet,Vascular Physiology,Lund University Research Groups(Swepub:lu)mphy-phe
(author)
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KärlfysiologiForskargrupper vid Lunds universitet
(creator_code:org_t)
Related titles
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In:American Journal of Physiology: Cell Physiology269:3, s. 563-5711522-1563
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