| First Author | Nyland LR | Year | 2009 |
| Journal | Biophys J | Volume | 96 |
| Issue | 8 | Pages | 3273-80 |
| PubMed ID | 19383471 | Mgi Jnum | J:166110 |
| Mgi Id | MGI:4839715 | Doi | 10.1016/j.bpj.2008.12.3946 |
| Citation | Nyland LR, et al. (2009) Cardiac myosin binding protein-C is essential for thick-filament stability and flexural rigidity. Biophys J 96(8):3273-80 |
| abstractText | Using atomic force microscopy, we examined the contribution of cardiac myosin binding protein-C (cMyBP-C) to thick-filament length and flexural rigidity. Native thick filaments were isolated from the hearts of transgenic mice bearing a truncation mutation of cMyBP-C (t/t) that results in no detectable cMyBP-C and from age-matched wild-type controls (+/+). Atomic force microscopy images of these filaments were evaluated with an automated analysis algorithm that identified filament position and shape. The t/t thick-filament length (1.48 +/- 0.02 microm) was significantly (P < 0.01) shorter than +/+ (1.56 +/- 0.02 microm). This 5%-shorter thick-filament length in the t/t was reflected in 4% significantly shorter sarcomere lengths of relaxed isolated cardiomyocytes of the t/t (1.97 +/- 0.01 microm) compared to +/+ (2.05 +/- 0.01 microm). To determine if cMyBP-C contributes to the mechanical properties of thick filaments, we used statistical polymer chain mechanics to calculate a per-filament-specific persistence length, an index of flexural rigidity directly proportional to Young's modulus. Thick-filament-specific persistence length in the t/t (373 +/- 62 microm) was significantly lower than in +/+ (639 +/- 101 microm). Accordingly, Young's modulus of t/t thick filaments was approximately 60% of +/+. These results provide what we consider a new understanding for the critical role of cMyBP-C in defining normal cardiac output by sustaining force and muscle stiffness. |
