Parvalbumins and muscle relaxation

a computer simulation study

J. M. Gillis, Donald Thomason, J. Lefèvre, R. H. Kretsinger

Research output: Contribution to journalArticle

136 Citations (Scopus)

Abstract

The distribution of Ca2+ and Mg2+ among the 'regulatory' cation binding sites of troponin (T-sites) and the strong, Ca2+-Mg2+ binding sites of troponin and parvalbumins (P-sites) in the sarcoplasm of a muscle was calculated. At rest, 60% of the T-sites were metal free, while 92% of the P-sites were loaded with Mg2+. In response to a Ca2+ pulse, troponin-calcium (T-Ca) complexes were rapidly formed, while the binding of Ca2+ to P-sites was limited by the slow rate of dissociation of the parvalbumin-magnesium (P-Mg) complexes. Muscle activation was not prevented by a high content of parvalbumins. Parvalbumin and the sarcoplasmic reticulum (SR) pump were complementary relaxing factors that removed Ca2+ from the cytosol and from the T-sites. Parvalbumins dominated the first part of relaxation, while the action of the SR was essential to ensure the return to a very low level of free Ca2+ ion and of T-Ca. After relaxation, a large fraction of the Ca2+ pulse was still bound to parvalbumins and returned slowly to the SR during the recovery. When the SR activity was reduced, the presence of parvalbumins preserved a fast rate of relaxation, at least for a few contractions. This may have a high adaptive value in cold-blooded animals.

Original languageEnglish (US)
Pages (from-to)377-398
Number of pages22
JournalJournal of Muscle Research and Cell Motility
Volume3
Issue number4
DOIs
StatePublished - Dec 1 1982

Fingerprint

Parvalbumins
Muscle Relaxation
Computer Simulation
Muscle
Sarcoplasmic Reticulum
Computer simulation
Troponin
Binding Sites
Muscles
Troponin T
Cytosol
Magnesium
Cations
Animals
Metals
Chemical activation
Pumps
Ions
Calcium
Recovery

All Science Journal Classification (ASJC) codes

  • Physiology
  • Biochemistry
  • Cell Biology

Cite this

Parvalbumins and muscle relaxation : a computer simulation study. / Gillis, J. M.; Thomason, Donald; Lefèvre, J.; Kretsinger, R. H.

In: Journal of Muscle Research and Cell Motility, Vol. 3, No. 4, 01.12.1982, p. 377-398.

Research output: Contribution to journalArticle

Gillis, J. M. ; Thomason, Donald ; Lefèvre, J. ; Kretsinger, R. H. / Parvalbumins and muscle relaxation : a computer simulation study. In: Journal of Muscle Research and Cell Motility. 1982 ; Vol. 3, No. 4. pp. 377-398.
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