Polyamines inhibit myosin phosphatase and increase LC20 phosphorylation and force in smooth muscle
Swärd, Karl LU ; Pato, M D ; Nilsson, Bengt-Olof LU
; Nordström, Ina
LU
and Hellstrand, Per
LU
(1995)
In American Journal of Physiology: Cell Physiology
269(3).
p.563-571
- Abstract
- 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... (More)
- 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. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1109022
- author
- Swärd, Karl
LU
; Pato, M D
; Nilsson, Bengt-Olof
LU
; Nordström, Ina
LU
and Hellstrand, Per
LU
- organization
- publishing date
- 1995-09
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Animals, Female, Gizzard, Guinea Pigs, Ileum, In Vitro Techniques, Muscle Contraction, Muscle, Smooth, Myosin Light Chains, Myosin-Light-Chain Kinase, Myosin-Light-Chain Phosphatase, Permeability, Phosphoprotein Phosphatases, Phosphoric Monoester Hydrolases, Phosphorylation, Polyamines, Spermine, Turkeys
- in
- American Journal of Physiology: Cell Physiology
- volume
- 269
- issue
- 3
- pages
- 563 - 571
- publisher
- American Physiological Society
- external identifiers
-
- pmid:7573385
- scopus:0029130591
- pmid:7573385
- ISSN
- 1522-1563
- language
- English
- LU publication?
- yes
- id
- a318afe9-3167-40d9-9a17-81d8381f4c66 (old id 1109022)
- alternative location
- http://ajpcell.physiology.org/cgi/reprint/269/3/C563
- date added to LUP
- 2016-04-01 16:24:07
- date last changed
- 2021-01-03 10:34:41
@article{a318afe9-3167-40d9-9a17-81d8381f4c66,
abstract = {{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.}},
author = {{Swärd, Karl and Pato, M D and Nilsson, Bengt-Olof and Nordström, Ina and Hellstrand, Per}},
issn = {{1522-1563}},
keywords = {{Animals; Female; Gizzard; Guinea Pigs; Ileum; In Vitro Techniques; Muscle Contraction; Muscle, Smooth; Myosin Light Chains; Myosin-Light-Chain Kinase; Myosin-Light-Chain Phosphatase; Permeability; Phosphoprotein Phosphatases; Phosphoric Monoester Hydrolases; Phosphorylation; Polyamines; Spermine; Turkeys}},
language = {{eng}},
number = {{3}},
pages = {{563--571}},
publisher = {{American Physiological Society}},
series = {{American Journal of Physiology: Cell Physiology}},
title = {{Polyamines inhibit myosin phosphatase and increase LC20 phosphorylation and force in smooth muscle}},
url = {{http://ajpcell.physiology.org/cgi/reprint/269/3/C563}},
volume = {{269}},
year = {{1995}},
}