Dilated cardiomyopathy mutation E525K in human beta-cardiac myosin stabilizes the interacting-heads motif and super-relaxed state of myosin

Rasicci, David V.; Tiwari, Prince; Bodt, Skylar M.L.; Desetty, Rohini; Sadler, Fredrik R; Sivaramakrishnan, Sivaraj; Craig, Roger; Yengo, Christopher M.

doi:10.7554/elife.77415

Cited by 17 publications

(34 citation statements)

References 79 publications

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“…Table 1), which we previously interpreted as evidence for the 15HEP construct adopting the IHM/SRX state 10,30 . Interestingly, the short-tailed, double-headed WT 2HEP construct displayed similar actin-activated ATPase activity to WT S1 (Fig.…”

Section: Wt M2β Steady-state Atpase Activitymentioning

confidence: 64%

“…3; Table 1). The IHM/SRX state in the long-tailed constructs is stabilized by intramolecular electrostatic interactions [8][9][10][11] , as evidenced by a reduced fraction of myosin in the IHM/SRX state with increasing ionic strength (i.e., 20mM to 150mM KCl) (Fig. 4c,d).…”

Section: Discussionmentioning

confidence: 94%

“…Garnering much attention is the super-relaxed, auto-inhibited myosin state (SRX) that can be stabilized by intramolecular interactions between myosin's two heads and its coiled-coil tail domain (i.e. interacting heads motif, IHM) 10,[40][41][42] . Therefore, the proportion of myosin that adopt this auto-inhibited IHM/SRX state effectively determines the number of available force-generating myosin heads upon activation (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…We previously studied the E525K DCM mutation and its impact on M2β structure and enzymatic activity 10 . However, we only compared the single-headed S1 and double-headed HMM 15HEP constructs.…”

Section: Wt M2β Steady-state Atpase Activitymentioning

confidence: 99%

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Tail Length and E525K Dilated Cardiomyopathy Mutant Alter Human β-Cardiac Myosin Super-Relaxed State

Duno-Miranda,

Nelson,

Rasicci

et al. 2023

Preprint

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Dilated cardiomyopathy (DCM) is characterized by impaired cardiac function due to myocardial hypo-contractility and is associated with point mutations in β-cardiac myosin, the molecular motor that powers cardiac contraction. Myocardial function can be modulated through sequestration of myosin motors into an auto-inhibited "super relaxed" state (SRX), which is further stabilized by a structural state known as the "Interacting Heads Motif" (IHM). Therefore, hypo-contractility of DCM myocardium may result from: 1) reduced function of individual myosin, and/or; 2) decreased myosin availability due to increased IHM/SRX stabilization. To define the molecular impact of an established DCM myosin mutation, E525K, we characterized the biochemical and mechanical activity of wild-type (WT) and E525K human β-cardiac myosin constructs that differed in the length of their coiled-coil tail, which dictates their ability to form the IHM/SRX state. Single-headed (S1) and a short-tailed, double-headed (2HEP) myosin constructs exhibited low (∼10%) IHM/SRX content, actin-activated ATPase activity of ∼5s-1and fast velocities in unloaded motility assays (∼2000nm/s). Double-headed, longer-tailed (15HEP, 25HEP) constructs exhibited higher IHM/SRX content (∼90%), and reduced actomyosin ATPase (<1s-1) and velocity (∼800nm/s). A simple analytical model suggests that reduced velocities may be attributed to IHM/SRX-dependent sequestration of myosin heads. Interestingly, the E525K 15HEP and 25HEP mutants showed no apparent impact on velocity or actomyosin ATPase at low ionic strength. However, at higher ionic strength, the E525K mutation stabilized the IHM/SRX state. Therefore, the E525K-associated DCM human cardiac hypo-contractility may be attributable to reduced myosin head availability caused by enhanced IHM/SRX stability.SummaryThis research investigates the E525K mutation in human β-cardiac myosin, crucial for heart contraction, and its role in causing Dilated Cardiomyopathy (DCM). It demonstrates that the length of the myosin tail influences its self-inhibition, and the E525K mutation strengthens this effect, potentially reducing heart contractility in DCM.

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Section: Wt M2β Steady-state Atpase Activitymentioning

confidence: 64%

Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Section: Wt M2β Steady-state Atpase Activitymentioning

confidence: 99%

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Tail Length and E525K Dilated Cardiomyopathy Mutant Alter Human β-Cardiac Myosin Super-Relaxed State

Duno-Miranda,

Nelson,

Rasicci

et al. 2023

Preprint

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“…Indeed, the variants stabilize the interacting heads motif and subsequent SRX conformation reducing the number of myosin heads available for recruitment. Fewer heads can enter the force-generating phase leading to hypo-contractility and having detrimental consequences for the pumping action of the heart [19, 20].…”

Section: Discussionmentioning

confidence: 99%

Predominant myosin super-relaxed state in canine myocardium with naturally occurring dilated cardiomyopathy

Ochala

Lewis

Beck

et al. 2023

Preprint

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Dilated cardiomyopathy (DCM) is a naturally occurring heart failure condition in humans and dogs, notably characterized by a reduced ejection fraction. As the identification of the underlying cellular and molecular mechanisms remain incomplete, the aim of the present study was to assess whether myosin and its known relaxed conformational states contribute to DCM aetiology. For that, we dissected and skinned thin cardiac strips from left ventricle obtained from six DCM Doberman Pinschers and six nonfailing controls (NF). We then used Mant-ATP chase experiments, X-ray diffraction and molecular simulations. We observed that, in DCM dogs, the amount of myosin heads in the stabilizing conformational state also known as super-relaxed (SRX) is significantly increased when compared with NF dogs. We also found that myosin heads are blocked in this SRX state preventing a proper length dependent activation, subsequently hindering myosin head recruitment and force-generating capacity. Despite these, our data also demonstrate that when applying EMD-57033, a small molecule activating myosin, SRX-related detrimental effects can be rescued. Taken together, our results suggest that myosin SRX contributes to the DCM pathophysiology and that the observed negative changes are reversible, giving hope for a myosin-centered pharmacological treatment of this particular cardiac disease.

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Myosin II Adjusts Motility Properties and Regulates Force Production Based on Motor Environment

et al. 2022

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Dilated cardiomyopathy mutation E525K in human beta-cardiac myosin stabilizes the interacting-heads motif and super-relaxed state of myosin

Cited by 17 publications

References 79 publications

Tail Length and E525K Dilated Cardiomyopathy Mutant Alter Human β-Cardiac Myosin Super-Relaxed State

Tail Length and E525K Dilated Cardiomyopathy Mutant Alter Human β-Cardiac Myosin Super-Relaxed State

Predominant myosin super-relaxed state in canine myocardium with naturally occurring dilated cardiomyopathy

Myosin II Adjusts Motility Properties and Regulates Force Production Based on Motor Environment

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