Cardiac ventricular myosin and slow skeletal myosin exhibit dissimilar chemomechanical properties despite bearing the same myosin heavy chain isoform

Wang, Tianbang; Spahiu, Emrulla; Osten, Jennifer; Behrens, Florentine; Grünhagen, Fabius; Scholz, Tim; Kraft, Theresia; Nayak, Arnab; Amrute-Nayak, Mamta

doi:10.1016/j.jbc.2022.102070

Cited by 5 publications

(6 citation statements)

References 76 publications

(86 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While the current study as well as the parallel optical trapping study on the single myosin molecule level primarily refer to rabbit M. soleus and ventricular myosin, it is possible that some effects of HCM-associated mutations in human M. soleus myosin may vary from those in ventricular myosin. Although values of, e.g., shortening velocity and crossbridge kinetics might vary between M. soleus and ventricular myosin, we could show in our recent single molecule study that other functional parameters such as stroke size and myosin rigor stiffness remained unchanged between ventricular and M. soleus myosin ( Wang et al, 2022 ). In previous studies, M. soleus fibers from HCM patients carrying point mutations in their MYH7 gene were compared to M. soleus fibers from healthy individuals.…”

Section: Discussionmentioning

confidence: 72%

“…In a parallel optical trapping study ( Wang et al, 2022 ), we investigated the chemomechanical properties of M. soleus and ventricular β-myosin at the single molecule level and found that the stroke sizes d of ventricular and M. soleus myosin were very comparable (5.32 ± 0.16 and 6 ± 0.19 nm, respectively). The lifetimes of actomyosin complexes, however, were increased significantly for M. soleus myosin molecules compared to ventricular β-myosin.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Myosin essential light chain 1sa decelerates actin and thin filament gliding on β-myosin molecules

Osten

Mohebbi

Uta

et al. 2022

Journal of General Physiology

Self Cite

View full text Add to dashboard Cite

The β-myosin heavy chain expressed in ventricular myocardium and the myosin heavy chain (MyHC) in slow-twitch skeletal Musculus soleus (M. soleus) type-I fibers are both encoded by MYH7. Thus, these myosin molecules are deemed equivalent. However, some reports suggested variations in the light chain composition between M. soleus and ventricular myosin, which could influence functional parameters, such as maximum velocity of shortening. To test for functional differences of the actin gliding velocity on immobilized myosin molecules, we made use of in vitro motility assays. We found that ventricular myosin moved actin filaments with ∼0.9 µm/s significantly faster than M. soleus myosin (0.3 µm/s). Filaments prepared from isolated actin are not the native interaction partner of myosin and are believed to slow down movement. Yet, using native thin filaments purified from M. soleus or ventricular tissue, the gliding velocity of M. soleus and ventricular myosin remained significantly different. When comparing the light chain composition of ventricular and M. soleus β-myosin, a difference became evident. M. soleus myosin contains not only the “ventricular” essential light chain (ELC) MLC1sb/v, but also an additional longer and more positively charged MLC1sa. Moreover, we revealed that on a single muscle fiber level, a higher relative content of MLC1sa was associated with significantly slower actin gliding. We conclude that the ELC MLC1sa decelerates gliding velocity presumably by a decreased dissociation rate from actin associated with a higher actin affinity compared to MLC1sb/v. Such ELC/actin interactions might also be relevant in vivo as differences between M. soleus and ventricular myosin persisted when native thin filaments were used.

show abstract

Section: Discussionmentioning

confidence: 72%

Section: Discussionmentioning

confidence: 99%

Myosin essential light chain 1sa decelerates actin and thin filament gliding on β-myosin molecules

Osten

Mohebbi

Uta

et al. 2022

Journal of General Physiology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Compound 2 was inactive against fast skeletal myofibrils and smooth muscle myosin but showed similar activity in the cardiac and slow skeletal myofibril assays (Figure ). The lack of selectivity between cardiac and slow skeletal myofibrils suggests that 2 may primarily interact with either cardiac myosin or the cardiac thin filament component troponin C (TnC) since both sarcomere constituents are shared between cardiac and slow skeletal muscle. , …”

Section: Resultsmentioning

confidence: 99%

“…The lack of selectivity between cardiac and slow skeletal myofibrils suggests that 2 may primarily interact with either cardiac myosin or the cardiac thin filament component troponin C (TnC) since both sarcomere constituents are shared between cardiac and slow skeletal muscle. 36,37 Cardiomyocyte experiments were performed to determine if 2 met the key objective of activating cardiac myofibrils without increasing calcium flux. Adult male Sprague−Dawley rat cardiomyocytes were stimulated at 1 Hz at 37 °C, and quiescent myocytes with well-defined striations were selected for contractility assessment.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Cardiac Troponin Activator CK-963 Increases Cardiac Contractility in Rats

Collibee,

Romero,

Muci

et al. 2024

J. Med. Chem.

View full text Add to dashboard Cite

Novel cardiac troponin activators were identified using a high throughput cardiac myofibril ATPase assay and confirmed using a series of biochemical and biophysical assays. HTS hit 2 increased rat cardiomyocyte fractional shortening without increasing intracellular calcium concentrations, and the biological target of 1 and 2 was determined to be the cardiac thin filament. Subsequent optimization to increase solubility and remove PDE-3 inhibition led to the discovery of CK-963 and enabled pharmacological evaluation of cardiac troponin activation without the competing effects of PDE-3 inhibition. Rat echocardiography studies using CK-963 demonstrated concentration-dependent increases in cardiac fractional shortening up to 95%. Isothermal calorimetry studies confirmed a direct interaction between CK-963 and a cardiac troponin chimera with a dissociation constant of 11.5 ± 3.2 μM. These results provide evidence that direct activation of cardiac troponin without the confounding effects of PDE-3 inhibition may provide benefit for patients with cardiovascular conditions where contractility is reduced.

show abstract

“…However, it is important to consider, in this connection, that other studies demonstrate a dramatic effect of essential 79,80 and regulatory 81,82 light chain isoforms on both striated muscle myosin ATPase kinetic properties and actin filament gliding velocities. Moreover, when performing experiments in parallel, Tang and coworkers 55 , observed that substitutions of the mouse regulatory chain for the human ventricular regulatory light chain (without exchange of the mouse ELC; study 3.1 vs 3.2 in Table S2) demonstrated reduced K ATPase and actin filament velocity by ~ 40% and ~ 15%, respectively (see also Fig.…”

Section: Parametersmentioning

confidence: 99%

Virus-free transfection, transient expression, and purification of human cardiac myosin in mammalian muscle cells for biochemical and biophysical assays

Velayuthan

Moretto

Tågerud

et al. 2023

Sci Rep

View full text Add to dashboard Cite

Myosin expression and purification is important for mechanistic insights into normal function and mutation induced changes. The latter is particularly important for striated muscle myosin II where mutations cause several debilitating diseases. However, the heavy chain of this myosin is challenging to express and the standard protocol, using C2C12 cells, relies on viral infection. This is time and work intensive and associated with infrastructural demands and biological hazards, limiting widespread use and hampering fast generation of a wide range of mutations. We here develop a virus-free method to overcome these challenges. We use this system to transfect C2C12 cells with the motor domain of the human cardiac myosin heavy chain. After optimizing cell transfection, cultivation and harvesting conditions, we functionally characterized the expressed protein, co-purified with murine essential and regulatory light chains. The gliding velocity (1.5–1.7 µm/s; 25 °C) in the in vitro motility assay as well as maximum actin activated catalytic activity (kcat; 8–9 s−1) and actin concentration for half maximal activity (KATPase; 70–80 µM) were similar to those found previously using virus based infection. The results should allow new types of studies, e.g., screening of a wide range of mutations to be selected for further characterization.

show abstract

Cardiac ventricular myosin and slow skeletal myosin exhibit dissimilar chemomechanical properties despite bearing the same myosin heavy chain isoform

Cited by 5 publications

References 76 publications

Myosin essential light chain 1sa decelerates actin and thin filament gliding on β-myosin molecules

Myosin essential light chain 1sa decelerates actin and thin filament gliding on β-myosin molecules

Cardiac Troponin Activator CK-963 Increases Cardiac Contractility in Rats

Virus-free transfection, transient expression, and purification of human cardiac myosin in mammalian muscle cells for biochemical and biophysical assays

Contact Info

Product

Resources

About