The role of the actin filament-associated protein nebulin on mechanical and kinetic properties of the actomyosin motor was investigated in skeletal muscle of wild-type (wt) and nebulin-deficient (nebulin(-)(/)(-)) mice that were 1 d old, an age at which sarcomeric structure is still well preserved. In Ca2+-activated skinned fibers from psoas muscle, we determined the Ca2+ dependence of isometric force and stiffness, the rate of force redevelopment after unloaded shortening (k(TR)), the power during isotonic shortening, and the unloaded shortening velocity (V(0)). Our results show a 65% reduction in isometric force in nebulin(-)(/)(-) fibers at saturating [Ca2+], whereas neither thin-filament length nor the Ca2+ sensitivity of the contractile system is affected. Stiffness measurements indicate that the reduction in isometric force is due to a reduction in the number of actin-attached myosin motors, whereas the force of the motor is unchanged. Furthermore, in nebulin(-)(/)(-) fibers, k(TR) is decreased by 57%, V(0) is increased by 63%, and the maximum power is decreased by 80%. These results indicate that, in the absence of nebulin, the attachment probability of the myosin motors to actin is decreased, revealing a direct role for nebulin in promoting strong actomyosin interactions responsible for force and power production.

Nebulin plays a direct role in promoting strong actin-myosin interactions / M.L. Bang; M. Caremani; E. Brunello; R. Littlefield; R.L. Lieber; J. Chen; V. Lombardi; M. Linari. - In: THE FASEB JOURNAL. - ISSN 0892-6638. - STAMPA. - 23(2009), pp. 4117-4125. [10.1096/fj.09-137729]

Nebulin plays a direct role in promoting strong actin-myosin interactions

CAREMANI, MARCO;BRUNELLO, ELISABETTA;LOMBARDI, VINCENZO;LINARI, MARCO
2009

Abstract

The role of the actin filament-associated protein nebulin on mechanical and kinetic properties of the actomyosin motor was investigated in skeletal muscle of wild-type (wt) and nebulin-deficient (nebulin(-)(/)(-)) mice that were 1 d old, an age at which sarcomeric structure is still well preserved. In Ca2+-activated skinned fibers from psoas muscle, we determined the Ca2+ dependence of isometric force and stiffness, the rate of force redevelopment after unloaded shortening (k(TR)), the power during isotonic shortening, and the unloaded shortening velocity (V(0)). Our results show a 65% reduction in isometric force in nebulin(-)(/)(-) fibers at saturating [Ca2+], whereas neither thin-filament length nor the Ca2+ sensitivity of the contractile system is affected. Stiffness measurements indicate that the reduction in isometric force is due to a reduction in the number of actin-attached myosin motors, whereas the force of the motor is unchanged. Furthermore, in nebulin(-)(/)(-) fibers, k(TR) is decreased by 57%, V(0) is increased by 63%, and the maximum power is decreased by 80%. These results indicate that, in the absence of nebulin, the attachment probability of the myosin motors to actin is decreased, revealing a direct role for nebulin in promoting strong actomyosin interactions responsible for force and power production.
23
4117
4125
M.L. Bang; M. Caremani; E. Brunello; R. Littlefield; R.L. Lieber; J. Chen; V. Lombardi; M. Linari
File in questo prodotto:
File Dimensione Formato  
Bang et al 2009.pdf

Accesso chiuso

Tipologia: Versione finale referata (Postprint, Accepted manuscript)
Licenza: DRM non definito
Dimensione 604.22 kB
Formato Adobe PDF
604.22 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2158/370131
Citazioni
  • ???jsp.display-item.citation.pmc??? 44
  • Scopus 57
  • ???jsp.display-item.citation.isi??? 54
social impact