A troponin switch that regulates muscle contraction by stretch instead of calcium

Bogos Agianian, Uroš Kržič, Feng Qiu, Wolfgang A. Linke, Kevin Leonard, Belinda Bullard

Research output: Contribution to journalArticle

57 Citations (Scopus)

Abstract

The flight muscles of many insects have a form of regulation enabling them to contract at high frequencies. The muscles are activated by periodic stretches at low Ca2+ levels. The same muscles also give isometric contractions in response to higher Ca2+. We show that the two activities are controlled by different isoforms of TnC (F1 and F2) within single myofibrils. F1 binds one Ca2+ with high affinity in the C-terminal domain and F2 binds one Ca2+ in the C-terminal domain and one exchangeable Ca2+ in the N-terminal domain. We have characterised the isoforms and determined their effect on the development of stretch-activated and Ca2+-activated tension by replacing endogenous TnC in Lethocerus flight muscle fibres with recombinant isoforms. Fibres with F1 gave stretch-activated tension and minimal isometric tension; those with F2 gave Ca2+-dependent isometric tension and minimal stretch-activated tension. Regulation by a TnC responding to stretch rather than Ca2+ is unprecedented and has resulted in the ability of insect flight muscle to perform oscillatory work at low Ca2+ concentrations, a property to which a large number of flying insects owe their evolutionary success.

Original languageEnglish (US)
Pages (from-to)772-779
Number of pages8
JournalEMBO Journal
Volume23
Issue number4
DOIs
StatePublished - Feb 25 2004
Externally publishedYes

Fingerprint

Troponin
Muscle Contraction
Muscle
Switches
Calcium
Muscles
Insects
Protein Isoforms
Isometric Contraction
Fibers
Myofibrils

Keywords

  • Ca regulation
  • Insect flight muscle
  • Stretch activation
  • Troponin C

ASJC Scopus subject areas

  • Genetics
  • Cell Biology

Cite this

A troponin switch that regulates muscle contraction by stretch instead of calcium. / Agianian, Bogos; Kržič, Uroš; Qiu, Feng; Linke, Wolfgang A.; Leonard, Kevin; Bullard, Belinda.

In: EMBO Journal, Vol. 23, No. 4, 25.02.2004, p. 772-779.

Research output: Contribution to journalArticle

Agianian, B, Kržič, U, Qiu, F, Linke, WA, Leonard, K & Bullard, B 2004, 'A troponin switch that regulates muscle contraction by stretch instead of calcium', EMBO Journal, vol. 23, no. 4, pp. 772-779. https://doi.org/10.1038/sj.emboj.7600097
Agianian, Bogos ; Kržič, Uroš ; Qiu, Feng ; Linke, Wolfgang A. ; Leonard, Kevin ; Bullard, Belinda. / A troponin switch that regulates muscle contraction by stretch instead of calcium. In: EMBO Journal. 2004 ; Vol. 23, No. 4. pp. 772-779.
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