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The effects of caldesmon extraction on mechanical properties of skinned smooth muscle fibre preparations

Malmqvist, Ulf LU ; Arner, A ; Makuch, R and Dabrowska, R (1996) In Pflügers Archiv 432(2). p.241-247
Abstract
The role of caldesmon in the regulation of smooth muscle contraction was investigated in chemically skinned smooth muscle fibres from the guinea-pig taenia coli. A 19-kDa C-terminal fragment of caldesmon gave a minor (<5%) reduction of force in fully thiophosphorylated fibres, but reduced force by about 50% at intermediate activation levels without affecting the level of light chain phosphorylation. An extraction procedure was developed using incubation in solutions containing high Mg2+ concentrations. Protein analysis revealed a selective decrease in the amount of caldesmon in the fibres. Maximal active force per cross-sectional area was unaffected. The Ca2+ dependence of active force was shifted towards lower Ca2+ concentrations and... (More)
The role of caldesmon in the regulation of smooth muscle contraction was investigated in chemically skinned smooth muscle fibres from the guinea-pig taenia coli. A 19-kDa C-terminal fragment of caldesmon gave a minor (<5%) reduction of force in fully thiophosphorylated fibres, but reduced force by about 50% at intermediate activation levels without affecting the level of light chain phosphorylation. An extraction procedure was developed using incubation in solutions containing high Mg2+ concentrations. Protein analysis revealed a selective decrease in the amount of caldesmon in the fibres. Maximal active force per cross-sectional area was unaffected. The Ca2+ dependence of active force was shifted towards lower Ca2+ concentrations and became less steep. The effects of extraction of caldesmon could in part be reversed by incubation in a solution containing purified caldesmon. The results are consistent with the hypothesis that caldesmon in smooth muscle thin filaments inhibits force generation and plays a role in regulating cooperative attachment of cross-bridges at sub-maximal levels of activation in smooth muscle. (Less)
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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Skinned smooth muscle, Caldesmon, 19-kDa fragment, Calcium sensitivity
in
Pflügers Archiv
volume
432
issue
2
pages
241 - 247
publisher
Springer
external identifiers
  • pmid:8662300
  • scopus:0029957346
ISSN
0031-6768
DOI
10.1007/s004240050130
language
English
LU publication?
yes
id
18d2527a-6aac-4742-aa7e-7b8cf9bc8a97 (old id 1110909)
date added to LUP
2016-04-01 17:01:42
date last changed
2022-01-28 23:50:13
@article{18d2527a-6aac-4742-aa7e-7b8cf9bc8a97,
  abstract     = {{The role of caldesmon in the regulation of smooth muscle contraction was investigated in chemically skinned smooth muscle fibres from the guinea-pig taenia coli. A 19-kDa C-terminal fragment of caldesmon gave a minor (&lt;5%) reduction of force in fully thiophosphorylated fibres, but reduced force by about 50% at intermediate activation levels without affecting the level of light chain phosphorylation. An extraction procedure was developed using incubation in solutions containing high Mg2+ concentrations. Protein analysis revealed a selective decrease in the amount of caldesmon in the fibres. Maximal active force per cross-sectional area was unaffected. The Ca2+ dependence of active force was shifted towards lower Ca2+ concentrations and became less steep. The effects of extraction of caldesmon could in part be reversed by incubation in a solution containing purified caldesmon. The results are consistent with the hypothesis that caldesmon in smooth muscle thin filaments inhibits force generation and plays a role in regulating cooperative attachment of cross-bridges at sub-maximal levels of activation in smooth muscle.}},
  author       = {{Malmqvist, Ulf and Arner, A and Makuch, R and Dabrowska, R}},
  issn         = {{0031-6768}},
  keywords     = {{Skinned smooth muscle; Caldesmon; 19-kDa fragment; Calcium sensitivity}},
  language     = {{eng}},
  number       = {{2}},
  pages        = {{241--247}},
  publisher    = {{Springer}},
  series       = {{Pflügers Archiv}},
  title        = {{The effects of caldesmon extraction on mechanical properties of skinned smooth muscle fibre preparations}},
  url          = {{http://dx.doi.org/10.1007/s004240050130}},
  doi          = {{10.1007/s004240050130}},
  volume       = {{432}},
  year         = {{1996}},
}