| First Author | Bang ML | Year | 2009 |
| Journal | FASEB J | Volume | 23 |
| Issue | 12 | Pages | 4117-25 |
| PubMed ID | 19679637 | Mgi Jnum | J:155171 |
| Mgi Id | MGI:4412421 | Doi | 10.1096/fj.09-137729 |
| Citation | Bang ML, et al. (2009) Nebulin plays a direct role in promoting strong actin-myosin interactions. FASEB J 23(12):4117-25 |
| abstractText | 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. |
