Myosin interactions involved in IHM assembly and myosin motor domain (MD) functions that are altered by PVs and LPVs are depicted. (A) Relaxed healthy cardiac muscle contains myosin heads …
(A) Quasi-atomic homologous model of human β-cardiac myosin interacting-heads motif (IHM) PDB 5TBY composed of blocked (BH) and free (FH) heads, fitted to the human cardiac thick filament 3D-map …
The comparison of model-based tarantula PDB 3JBH (blue dashed line) vs. human cardiac ventricular IHM PDB 5TBY (red line) scattering with measured squid HMM scattering profiles (green dots) in (A) …
(A) Superimposed MDs of S1 from the PDB 5TBY antavd a S1 fragment of human β-cardiac myosin S1 crystal structure PDB 4DB1 (AMPPNP rigor-like structure) See Video 2. Color code: PDB 5TBY: Blocked …
Each variant appears as a pair, one located on or associated with the blocked head (BH, olive) and one on the free head (FH, green). Associated proteins are the essential light chain (ELC …
(A) IHM PDB 5TBY model mapping 40 HCM pathogenic variants (that produced 39 distinct substitutions in MHC and four substitutions in the regulatory and essential light chains; Table 1, in the main …
Three variants alter resides that participate in ‘f’ sub-interactions (‘f.1’: D906G, L908V; ‘f.2’: R663H) and two alter residues that participate in ‘g’ interactions (R453C and R870H). All chains …
Intermolecular interactions between (‘j’, ‘i’) myosin and the essential light chain anchor the blocked head anchoring on the neighboring S2. Five substitutions are involved on interaction ‘j’ …
Twenty-three MHC variants and two ELC variants alter IHM residues that dock the free head onto the blocked head (‘e’, ‘d’ and ‘a’ interactions). Nineteen MYH7 substitutions are at residues …
Variants in MHC (S842N and F834L) and RLC (E22K and R58Q) alter residues that allow proper docking of the two opposite surfaces of the RLC-RLC interface when the IHM is initially assembled. The …
Variant positions (arrowheads) are color-coded according their charge-change, as in Figure 3—figure supplement 1.
Variant positions (arrowheads) are color-coded as in Figure 3—figure supplement 1.
HCM variant positions are (arrowheads) color-coded as in Figure 3—figure supplement 1.
HCM variant positions are (arrowheads) color-coded as in Figure 3—figure supplement 1.
The three negatively-charged rings in the blocked head S2 are labeled R1, R2 and R3. The associated sarcomere proteins are depicted as in Figure 3. The myosin mesas are roughly orthogonal (blocked …
The PDB 5TBY IHM model is initially depicted as a ribbon structure that includes paired myosin heads (blocked head (BH), gold, free head (FH), olive), essential light chain (ELC associated with BH: …
The movie shows superimposed MDs of S1s from the PDB 5TBY model and a S1 fragment of PDB 4DB1 (S1 bound to adenylylimidodiphosphate (AMPPNP), a nonhydrolysable analogue of ATP to induce a rigor-like …
The movie shows the two S2 strands as ribbons of PDB 5TBY in gold and olive (blocked and free heads, respectively) and 2FXM in pink. See legend of Figure 2—figure supplement 2B.
The movie shows the free and blocked head structures of PDB 5TBY IHM model as ribbons in gold and olive respectively, versus the pre-powerstroke state PDB 1BR1 crystal structure (magenta). The ELC …
HCM variants reside on the myosin blocked head (gold), myosin free head (olive), essential light chain (associated with blocked head (brown) or free head, (purple)), and regulatory light chain …
Variants are depicted as balls, colored according to the interactions that that disrupt: priming, green; anchoring, orange; stabilizing, pink, and scaffolding, white. Grey variants alter residues …
The myosin blocked head (gold), myosin free head (olive), essential light chain (associated with blocked head (brown) or free head (purple)), and regulatory light chain (associated with blocked head …
HCM pathogenic variants (PVs) causing 39 MYH7, 2 MYL2, and 2 MYL3 amino acid substitutions.
Substitution | Location* | BH interaction* | Type* | FH interaction* | Type* | Δq† | Motor Domain Function‡ |
---|---|---|---|---|---|---|---|
MYH7 | Motor Domain | ||||||
Y115H | Near ATP Binding I | +1 | |||||
E170K | Near ATP-binding II | d.1 | Stabilizing | +2 | |||
R249Q | Near ATP Binding III | -2 | |||||
I263T | Near ATP Binding IV | 0 | |||||
P307H | Near ATP Binding IV | +1 | |||||
R403W/G/L/Q | CM-Loop | d.1 | Stabilizing | -2 | Actin interface 1 | ||
R442C | Near ATP Binding V | d.1 | Stabilizing | -2 | |||
R453C | Near ATP Binding V | g | Priming | d.1 | Stabilizing | -2 | |
E483K | Near Relay | j | Anchoring | d.2 | Stabilizing | +2 | |
M515T | Relay | j | Anchoring | d.2 | Stabilizing | 0 | Relay |
V606M | Helix-loop-helix | e | Stabilizing | 0 | Actin interface | ||
R663H | Near Loop 2 | f.2 | Priming | -1 | |||
M690T | SH2 helix | 0 | |||||
I702N | SH1 helix | 0 | |||||
G708A | SH1 helix | 0 | |||||
G716R | Converter | i | Anchoring | d.2 | Stabilizing | +2 | Converter |
ELC-MHC | Scaffolding | Converter | |||||
R719W/Q | Converter | i, | Anchoring | d.2 | Stabilizing | -2 | Converter |
ELC-MHC | Scaffolding | Converter | |||||
R723G/C | Converter | i | Anchoring | d.2 | Stabilizing | -2 | Converter |
ELC-MHC | Scaffolding | Converter | |||||
I736T | Converter | j | Anchoring | d.2 | Stabilizing | 0 | Converter |
ELC-MHC | Scaffolding | Converter | |||||
G741W / R | Converter | j | Anchoring | d.2 | Stabilizing | 0 / + 2 | Converter |
ELC-MHC | Scaffolding | Converter | |||||
K762R | Converter | j | Anchoring | d.2 | Stabilizing | +1 | Converter |
ELC-MHC | Scaffolding | Converter | |||||
K766Q | Converter | d.2 | Stabilizing | -1 | Converter | ||
Regulatory Domain | |||||||
A797T | Neck-ELC interface | ELC-MHC | Scaffolding | ELC-MHC | Scaffolding | 0 | |
F834L | Head-tail junction | RLC-MHC | Scaffolding | RLC-MHC | Scaffolding | 0 | |
S2 | |||||||
S842N | Head-tail junction | RLC-MHC | Scaffolding | RLC-MHC | Scaffolding | 0 | |
R870H | Kink | g | Priming | g | Priming | -1 | |
D906G | Ring1 | f.2 | Priming | f.2 | Priming | +1 | |
L908V | Ring1 | f.2 | Priming | f.2 | Priming | 0 | |
L915P | Ring2 | a | Stabilizing | a | Stabilizing | 0 | |
E924K | Ring2 | a | Stabilizing | a | Stabilizing | +2 | |
E930K | Ring2 | a | Stabilizing | a | Stabilizing | +2 | |
Light Meromyosin | |||||||
A1379T | Near skip 2 residue | 0 | |||||
R1781C | Near skip 4 residue | -2 | |||||
MYL3 | Essential Light Chain | ||||||
M149V | Chain F | i | Anchoring | e | Stabilizing | 0 | |
ELC-MHC | Scaffolding | ||||||
H155D | Chain F | i | Anchoring | ELC-MHC | Scaffolding | -2 | |
ELC-MHC | Scaffolding | e | Stabilizing | ||||
MYL2 | Regulatory Light Chain | ||||||
E22K | Near S15 | RLC-RLC | Regulating | RLC-RLC | Regulating | +2 | |
RLC-MHC | Scaffolding | RLC-MHC | Scaffolding | ||||
R58Q | Chains B-C loop | RLC-RLC | Regulating | -2 | |||
RLC-MHC | Scaffolding | RLC-MHC | Scaffolding |
All PVs identified in 6112 HCM patients (Walsh et al., 2017) are shown. In MYH7 there are 40 PVs, leading to 39 distinct substitutions at 33 positions while in MYL2 and MYL3 there are four more pathogenic variants. HCM PVs located on the mesa are bolded.
*Supplementary file 1 defines domain locations and Supplementary file 2 defines IHM interactions, refined using the PISA analysis (Krissinel and Henrick, 2007) that are highlighted as in Figure 3, excluding the two LMM substitutions. RLC–RLC denotes interface region between regulatory light chains.
†Δq: variant induced electrical charge change. Δq defines whether the substituted amino acid changes the charge (bolded) or not (Δq = 0).
‡Motor domain functions are ascribed only to variants within involved residues. RLC–RLC denotes interface region between regulatory light chains. Variants at IHM interactions sites are colored according to the interaction affected: priming = green, anchoring = orange, stabilizing = pink, scaffolding = white, regulating = yellow.
HCM likely pathogenic variants (LPVs) causing 95 MYH7 amino acid substitutions.
Substitution | Location* | BH interaction* | Type* | FH interaction* | Type* | Δq‡ | Motor Domain Function§ |
---|---|---|---|---|---|---|---|
MYH7 | Motor Domain | ||||||
R17C | SH3 | h | Anchoring | -2 | |||
R143Q | -2 | ||||||
K146N | -1 | ||||||
R169G/K/S | Near P-loop | d.1 | Stabilizing | −2/–1/−2 | |||
Q193R | Near P-loop | +2 | |||||
A199V | Near Loop 1 | 0 | |||||
R204C | Loop 1 | -2 | Actin interface | ||||
G214D | Loop 1 | -1 | Actin interface | ||||
N232H | Near Switch 2 | +1 | |||||
D239N | Switch 1 | +1 | ATP-Binding III | ||||
R243H† | Switch 1 | -1 | ATP-Binding III | ||||
F244C | Switch 1 | 0 | ATP-Binding III | ||||
K246I | Near Switch 1 | -1 | |||||
F247L | Near Switch 1 | 0 | |||||
I248T | Near Switch 1 | 0 | |||||
G256E | Near Switch 1 | -1 | |||||
I263M | Near ATP-Binding IV | 0 | |||||
L267V | Near ATP-Binding IV | 0 | |||||
Y283C | 0 | ||||||
S291F | Near I-loop | 0 | |||||
D309N | I-loop | +1 | MD-RLC interface | ||||
I323N | I-loop | 0 | MD-RLC interface | ||||
E328G | Near I-loop | +1 | |||||
V338M | 0 | ||||||
K351E | Near C-loop | -2 | |||||
G354S | Near C-loop | 0 | |||||
E374V | C-Loop | d.2 | Stabilizing | +1 | Actin interface | ||
A381D | C-Loop | d.2 | Stabilizing | -1 | Actin interface | ||
Y386C | Near C-loop | e | Stabilizing | 0 | |||
V406M | CM-loop | d.1 | Stabilizing | 0 | Actin Interface I | ||
Y410D | CM-loop | d.1 | Stabilizing | -1 | Actin Interface I | ||
V411I | CM-loop | d.1 | Stabilizing | 0 | Actin Interface I | ||
L427M | 0 | ||||||
T449S | Near Switch 2 | g | Priming | d.1 | Stabilizing | 0 | |
R453S/H | Near Switch 2 | g | Priming | d.1 | Stabilizing | 0/–1 | |
I457T | Near Switch 2 | 0 | |||||
I478N | Near Switch 2 | 0 | |||||
N479S | Near Switch 2 | 0 | |||||
M493V/L/I | Relay | j | Anchoring | d.2 | Stabilizing | 0 | Relay |
E497G/D | Relay | j | Anchoring | d.2 | Stabilizing | +1/0 | Relay |
1521T | Near Relay | 0 | |||||
E536D | H-loop | f.2 | Priming | 0 | Actin Interface II | ||
H576R | Loop 3 | +1 | Actin Interface III | ||||
G584R | Near Loop 3 | +2 | |||||
V586A | Near Loop 3 | 0 | |||||
R652G | Near Loop 2 | f.2 | Priming | -2 | |||
K657Q | Near Loop 2 | f.2 | Priming | -1 | |||
R663C | Near Loop 2 | f.2 | Priming | -2 | |||
R671C | Near SH2 helix | -2 | |||||
R694C/H | SH2 helix | −2/–1 | |||||
P710H/L | Converter | +1/0 | Converter | ||||
P731A | Converter | j | Anchoring | 0 | Converter | ||
ELC-MHC | Scaffolding | ||||||
G733E | Converter | j | Anchoring | d.2 | Stabilizing | -1 | Converter |
ELC-MHC | Scaffolding | ||||||
R739S | Converter | j | Anchoring | d.2 | Stabilizing | -2 | Converter |
ELC-MHC | Scaffolding | ||||||
K740N | Converter | j | Anchoring | d.2 | Stabilizing | -1 | Converter |
ELC-MHC | Scaffolding | ||||||
L749Q | Converter | j | Anchoring | 0 | Converter | ||
ELC-MHC | Scaffolding | ||||||
F758C | Converter | j | Anchoring | 0 | Converter | ||
ELC-MHC | Scaffolding | ||||||
V763M | Converter | d.2 | Stabilizing | 0 | Converter | ||
G768R | Converter | +2 | Converter | ||||
L781P | Pliant | ELC-MHC | Scaffolding | ELC-MHC | Scaffolding | 0 | Pivot |
R783H | Pliant | ELC-MHC | Scaffolding | ELC-MHC | Scaffolding | -1 | Pivot |
Regulatory Domain | |||||||
R787C | Neck-ELC interface | ELC-MHC | Scaffolding | ELC-MHC | Scaffolding | -2 | |
A797P | Neck-ELC interface | ELC-MHC | Scaffolding | ELC-MHC | Scaffolding | 0 | |
L811P | Neck-ELC-RLC interface | ELC-MHC RLC-MHC | Scaffolding | RLC-MHC | Scaffolding | 0 | |
S2 | |||||||
K847E | Head-tail junction | -2 | |||||
E848G | Head-tail junction | +1 | |||||
M849T | Head-tail junction | ||||||
A850D | Head-tail junction | -1 | |||||
R858H | g | Priming | g | Priming | -1 | ||
E894G | Ring 1 | f.1 | Priming | f.2 | Priming | +1 | |
L898V | Ring 1 | f.1 | Priming | f.2 | Priming | 0 | |
A901P | Ring 1 | f.1 | Priming | f.2 | Priming | 0 | |
E903G | Ring 1 | f.1 | Priming | f.2 | Priming | +1 | |
Q914H | +1 | ||||||
D928N | Ring 2 | a | Stabilizing | a | Stabilizing | +1 | |
E929K | Ring 2 | a | Stabilizing | a | Stabilizing | +2 | |
E930Q | Ring 2 | a | Stabilizing | a | Stabilizing | +1 | |
E949K | Ring 3 | +2 | |||||
E967K | +2 | ||||||
R1053Q | -2 | ||||||
Light Meromyosin | |||||||
E1356K | +2 | ||||||
R1382Q | Near skip 2 residue | -2 | |||||
L1428S | 0 | ||||||
R1606C | Near skip 3 residue | -2 | |||||
A1763T | 0 | ||||||
R1781H | Near skip 4 residue | -1 | |||||
M1782V | Near skip 4 residue |
All LPVs identified in 6112 HCM patients (Walsh et al., 2017) are shown. In MYH7 there 95 LPVs, leading to 95 distinct amino acid substitutions at 87 positions.
*Supplementary file 1 defines domain locations and Supplementary file 2 defines IHM interactions, refined using the PISA analysis (Krissinel and Henrick, 2007) that are highlighted as in Figure 3, excluding the LMM variants. HCM LPVs located on the mesa are bolded.
†R243H was identified in both HCM and DCM cohorts. RLC–RLC denotes interface region between regulatory light chains.
‡Δq: variant induced electrical charge change. Δq defines whether the substituted amino acid changes the charge (bolded) or not (Δq = 0).
§Motor domain functions are ascribed only to variants within involved residues. Variants at IHM interactions sites are colored according to the interaction affected: priming = green, anchoring = orange, stabilizing = pink, scaffolding = white.
DCM pathogenic variants (PVs) and likely pathogenic variants (LPVs) causing 27 MYH7 amino acid substitutions.
Substitution | Location‡ | BH interaction‡ | Type‡ | FH interaction‡ | Type‡ | Δq§ | Motor Domain Function¶ |
---|---|---|---|---|---|---|---|
MYH7 | Motor Domain | ||||||
G144V | Near ATP Binding I | 0 | |||||
G178R | ATP-binding II (P-loop) | +2 | ATP Binding II | ||||
G181R | ATP-binding II (P-loop) | +2 | ATP Binding II | ||||
I201T | Near 25/50 junction (Loop 1) | 0 | |||||
R243H† | ATP-binding III (Switch 1) | -1 | ATP Binding III | ||||
G245E | ATP-binding III (Switch 1) | -1 | ATP Binding III | ||||
I248F | Near ATP-binding III | 0 | |||||
R369Q | C-Loop (Loop 4) | d.2 | Stabilizing | -2 | Actin interface | ||
D469Y | ATP-binding V (Switch 2) | +1 | ATP Binding V | ||||
I524V | Near H-Loop | f.2 | Priming | 0 | |||
E525K | Near H-Loop | f.2 | Priming | +2 | |||
I533V | H-Loop | f.2 | Priming | 0 | Actin interface II | ||
R567H | Actin-interface III (Loop 3) | -1 | Actin interface III | ||||
N597K | Helix-loop-helix | +1 | Actin interface | ||||
C672F | Near SH2 Helix | 0 | |||||
R783P | Pliant | ELC-MHC | Scaffolding | ELC-MHC | Scaffolding | -2 | Pivot |
S2 | |||||||
R904C*/H | Ring1 | f.2 | Priming | f.2 | Priming | −2/–1 | |
E1152V | +1 | ||||||
Light Meromyosin | |||||||
R1193H | Near skip 1 residue | -1 | |||||
E1286K | +2 | ||||||
R1434C | -2 | ||||||
D1450N | +1 | ||||||
R1574W | -2 | ||||||
Q1794E | -1 | ||||||
E1801K | Near skip 4 residue | +2 | |||||
E1914K | +2 | . |
All PVs and LPVs identified in 1315 DCM patients (Walsh et al., 2017) are shown. In MYH7 there are 27 DCM pathogenic and likely pathogenic variants, leading to 27 distinct substitutions at 26 residues. DCM LPVs located on the mesa are bolded.
*R904C is the only DCM PV.
†R243H was identified in both HCM and DCM cohorts. In this cohort, no variants in MYL2 or MYL3 caused DCM.
‡Supplementary file 1 defines domain locations and Supplementary file 2 defines IHM interactions, refined using the PISA analysis (Krissinel and Henrick, 2007) that are highlighted as in Figure 3, excluding the LMM variants.
§Δq: variant induced electrical charge change. Δq defines whether the substituted amino acid changes the charge (bolded) or not (Δq = 0).
¶Motor domain functions are ascribed only to variants within involved residues. Variants at IHM interactions sites are colored according to the interaction affected: priming = green, stabilizing = pink, scaffolding = white.
The distribution of HCM variants across IHM and MD functional residues.
Specified site | Variants within site | Rate | Amino acids within site | Expected rate | Rate ratio | P-value |
---|---|---|---|---|---|---|
IHM Interactions (All) | 73 | 0.541 | 447 | 0.2310 | 2.34 | 7.95e-15 |
Priming | 17 | 0.126 | 113 | 0.0584 | 2.16 | 2.64e-03 |
Anchoring | 24 | 0.178 | 156 | 0.0806 | 2.21 | 2.11e-04 |
Stabilizing | 48 | 0.356 | 189 | 0.0977 | 3.64 | 5.37e-16 |
Scaffolding | 24 | 0.178 | 120 | 0.0620 | 2.87 | 2.97e-06 |
MD Functional | 39 | 0.289 | 194 | 0.1000 | 2.89 | 7.87e-10 |
The numbers of distinct pathogenic and likely pathogenic HCM variants (n = 135) affecting IHM interaction sites and motor domain (MD) functional residues are shown. Variant numbers are also tabulated separately for the four major IHM interactions: priming, anchoring, stabilizing and scaffolding. Note that a single variant may impact more than one interaction. The number of myosin amino acid residues (total protein length = 1935 residues) that compromise the IHM interaction sites or MD functions was used to determine the proportion of variants that would be expected to lie in the region of interest under the null (a uniform distribution), and the rates are compared with a binomial test. Full details of all variants are shown in Tables 1 and 2.
The distribution of DCM variants across IHM and MD functional residues.
Specified site | Variants within site | Rate | Amino acids within site | Expected rate | Rate ratio | P-value |
---|---|---|---|---|---|---|
IHM Interactions (All) | 7 | 0.259 | 447 | 0.2310 | 1.120 | 0.6550 |
Priming | 5 | 0.185 | 113 | 0.0584 | 3.170 | 0.0186 |
Anchoring | 0 | 0.000 | 156 | 0.0806 | 0.000 | 0.1650 |
Stabilizing | 1 | 0.037 | 189 | 0.0977 | 0.379 | 0.5120 |
Scaffolding | 1 | 0.037 | 120 | 0.0620 | 0.597 | 1.0000 |
MD Functional | 7 | 0.259 | 210 | 0.1090 | 2.380 | 0.0222 |
The numbers of distinct pathogenic and likely pathogenic DCM variants (n = 27) affecting IHM interactions and motor domain (MD) functional residues are shown. Variant numbers are also tabulated separately for the four major IHM interactions: priming, anchoring, stabilizing and scaffolding. Note that a single variant may impact more than one interaction. The number of myosin amino acid residues (total protein length = 1935 residues) that compromise the IHM interaction sites or MD functions was used to determine the proportion of variants that would be expected to lie in the region of interest under the null (a uniform distribution), and the rates are compared with a binomial test. Full details of all variants are shown in Table 3.
Domains of human β-cardiac myosin.
Intra- and inter-molecular interactions sequences involved in human β-cardiac myosin interacting-heads motif (IHM) PDB 5TBY.
HCM variants cluster on residues involved in IHM-related inter- and intra-molecular interactions.
DCM-causing variants cluster in distinct regions of MYH7 from HCM-causing variants.
Variants Clustered on the Myosin Mesa.
Comparison of prevalence of rare (ExAC global AF <1×10−4) missense variants in MYH7 in 6112 HCM cases and ExAC controls.
Leveraging regional distribution for the clinical interpretation of DCM-causing variants.