scholarly journals Identification of sequence changes in myosin II that adjust muscle contraction velocity

PLoS Biology ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. e3001248
Author(s):  
Chloe A. Johnson ◽  
Jake E. McGreig ◽  
Sarah T. Jeanfavre ◽  
Jonathan Walklate ◽  
Carlos D. Vera ◽  
...  
Keyword(s):  
Muscle Contraction ◽  
Body Mass ◽  
Myosin Ii ◽  
Sequence Divergence ◽  
Fold Increase ◽  
Motor Domain ◽  
Type I ◽  
Contraction Velocity ◽  
Contraction Speed ◽  
Adp Release

The speed of muscle contraction is related to body size; muscles in larger species contract at slower rates. Since contraction speed is a property of the myosin isoform expressed in a muscle, we investigated how sequence changes in a range of muscle myosin II isoforms enable this slower rate of muscle contraction. We considered 798 sequences from 13 mammalian myosin II isoforms to identify any adaptation to increasing body mass. We identified a correlation between body mass and sequence divergence for the motor domain of the 4 major adult myosin II isoforms (β/Type I, IIa, IIb, and IIx), suggesting that these isoforms have adapted to increasing body mass. In contrast, the non-muscle and developmental isoforms show no correlation of sequence divergence with body mass. Analysis of the motor domain sequence of β-myosin (predominant myosin in Type I/slow and cardiac muscle) from 67 mammals from 2 distinct clades identifies 16 sites, out of 800, associated with body mass (padj < 0.05) but not with the clade (padj > 0.05). Both clades change the same small set of amino acids, in the same order from small to large mammals, suggesting a limited number of ways in which contraction velocity can be successfully manipulated. To test this relationship, the 9 sites that differ between human and rat were mutated in the human β-myosin to match the rat sequence. Biochemical analysis revealed that the rat–human β-myosin chimera functioned like the native rat myosin with a 2-fold increase in both motility and in the rate of ADP release from the actin–myosin crossbridge (the step that limits contraction velocity). Thus, these sequence changes indicate adaptation of β-myosin as species mass increased to enable a reduced contraction velocity and heart rate.

scholarly journals Adaptation of mammalian myosin II sequences to body mass

2016 ◽  
Author(s):  
Jake E McGreig ◽  
Sarah T Jeanfavre ◽  
Charlotte Henson ◽  
Michael P Coghlan ◽  
Jonathan Walklate ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Mass ◽  
Myosin Ii ◽  
Sequence Divergence ◽  
Fold Increase ◽  
Motor Domain ◽  
Slow Skeletal Muscle ◽  
Cardiac Ventricle ◽  
Heart Beating ◽  
Myosin Motor Domain

AbstractThe speed of muscle contraction is related to body size; muscles in larger species contract at a slower rate. We investigated the evolution of twelve myosin II isoforms to identify any adapted to increasing body mass in mammals. We identified a correlation between body mass and sequence divergence for the motor domain of three adult myosin II isoforms (β, 2A, 2B) suggesting that these isoforms have adapted to increasing body mass. In contrast the non-muscle and developmental isoforms show no correlation of sequence divergence with body mass, while the sarcomeric myosin 7b, extraocular and 2X isoforms showed a divergence intermediate between these two groups. The 2B and β-myosin motor domain showed the greatest rate of sequence divergence (−0.84 and −0.69 % per ten-fold increase in mass respectively). β-myosin is abundant in cardiac ventricle and slow skeletal muscle. We propose that β-myosin has adapted to enable slower heart beating and contraction of slow skeletal muscle as body mass increased.

scholarly journals Cardiac contraction velocity has evolved to match heart rate with body size through variation in β-cardiac myosin sequence

2019 ◽  
Author(s):  
Chloe A. Johnson ◽  
Jake E. McGreig ◽  
Carlos D. Vera ◽  
Dan P. Mulvihill ◽  
Martin Ridout ◽  
...  
Keyword(s):  
Heart Rate ◽  
Biochemical Analysis ◽  
Striated Muscle ◽  
Maximum Velocity ◽  
Fold Increase ◽  
Cardiac Contraction ◽  
Contraction Velocity ◽  
Small Set ◽  
Adp Release ◽  
Contracting Heart

AbstractHeart rate and the maximum velocity of contraction of striated muscle are inversely related to species size. As mammals evolve to different sizes, adaptations are required such as slower contracting heart and skeletal muscles. Analysis of the motor domain of β-myosin from 67 mammals from two clades identifies 14 sites, out of 800, strongly associated with body mass (p<0.01) but not with the clade (p>0.05). Nine of these sites were mutated in the human β-myosin to make it resemble the rat sequence. Biochemical analysis revealed that the rat-human β-myosin chimera functioned like the native rat myosin with a two fold increase in both motility and in the rate of ADP release from the actin.myosin cross-bridge (the step that limits contraction velocity). Both clades use the same small set of amino acids to adjust contraction velocity, suggesting a limited number of ways in which velocity can be manipulated.

Browning of White Adipocytes in Fat Grafts Associated with Higher Level of Necrosis and Type 2 Macrophages Recruitment

2021 ◽  
Author(s):  
Tong Liu ◽  
Su Fu ◽  
Qian Wang ◽  
Hao Cheng ◽  
Dali Mu ◽  
...  
Keyword(s):  
Fold Increase ◽  
Chow Diet ◽  
Sham Operation ◽  
Type I ◽  
Electronic Microscopy ◽  
Fat Transfer ◽  
Fat Grafts ◽  
Female Nude ◽  
Normal Chow

Abstract Background Induced browning adipocytes were assumed less viable and more prone to necrosis for their hypermetabolic property. Our previous study showed that browning of adipocytes was more evident in fat grafts with necrosis in humans. Objectives We aimed to estimate whether fat-transfer-induced browning biogenesis was associated with necrosis and its potential inflammation mechanisms in murine models. Methods Human subcutaneous adipose from thigh or abdomen of 5 patients via liposuction were injected in 100µl or 500µl (n=20 per group) into the dorsal flank of 6-8-week female nude mice fed with normal chow diet, and harvested after 2, 4, 8 and 12 weeks. Control groups did not receive any grafting procedures (sham operation), where lipoaspirates were analyzed immediately after harvest. Histology and electronic microscopy, immunological analyses of browning markers, necrosis marker, and type I/II macrophages markers in mice were performed. Results Histology and electronic microscopy showed browning adipocytes in in fat grafts with higher level of necrosis (0.435±0.017pg/ml for cleaved caspase-3, **p&lt;0.01), IL-6(749.0±134.1pg/ml,***p&lt;0.001) and infiltration of type 2 macrophage profiles in mice(2-fold increase, *p&lt;0.05). Conclusions Browning of adipocytes induced by fat transfer in mice is in parallel with post-grafting necrotic levels, associated with elevated IL-6 and activated M2 macrophages profiles which promote browning development.

scholarly journals Relationship between Emotional Intelligence, Sleep Quality and Body Mass Index in Emergency Nurses

Healthcare ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 607
Author(s):  
Noelia Miguez-Torres ◽  
Alejandro Martínez-Rodríguez ◽  
María Martínez-Olcina ◽  
Laura Miralles-Amorós ◽  
Cristina Reche-García
Keyword(s):  
Body Mass Index ◽  
Emotional Intelligence ◽  
Sleep Quality ◽  
Body Mass ◽  
Working Hours ◽  
Type I ◽  
Emotional States ◽  
Emergency Nurses ◽  
Cross Sectional ◽  
Lack Of Sleep

Nurses have long working hours with high psychological burdens. In addition, in the emergency department, nurses are required to quickly adapt emotionally. The aim of this study was to describe and relate emotional intelligence (EI) skills of emergency nurses, their body mass index (BMI) and sleep quality. For this purpose, a cross-sectional was carried out in which the perceived emotional intelligence test and the Pittsburgh sleep quality index were applied. Sixty-two emergency nurses (48 women and 14 men) participated. The results indicated that the majority of them present adequate levels of EI, with no differences by gender. Younger nurses showed a better ability to feel, express and understand emotional states than the older ones, while the ability to regulate emotional states occurred in the opposite way. Nurses who have been working for several years showed a better ability to regulate emotions than those with less experience. Those who were overweight grade II and obese type I expressed their feelings better, also the regulation of emotional states decreased as weight increased. Finally, it has been observed that the quality of sleep of emergency nurses is significantly altered, and that this lack of sleep may affect their ability to process emotions.

scholarly journals Adrenergic control of vascular resistance varies in muscles composed of different fiber types: influence of the vascular endothelium

2011 ◽  
Vol 301 (3) ◽  
pp. R783-R790 ◽  
Author(s):  
Bradley J. Behnke ◽  
Robert B. Armstrong ◽  
Michael D. Delp
Keyword(s):  
Blood Flow ◽  
Vascular Resistance ◽  
Vascular Endothelium ◽  
Fold Increase ◽  
Male Rats ◽  
Type I ◽  
Fiber Types ◽  
Fast Twitch Muscle ◽  
Dose Responses ◽  
Fast Twitch

The influence of the sympathetic nervous system (SNS) upon vascular resistance is more profound in muscles comprised predominately of low-oxidative type IIB vs. high-oxidative type I fiber types. However, within muscles containing high-oxidative type IIA and IIX fibers, the role of the SNS on vasomotor tone is not well established. The purpose of this study was to examine the influence of sympathetic neural vasoconstrictor tone in muscles composed of different fiber types. In adult male rats, blood flow to the red and white portions of the gastrocnemius (GastRed and GastWhite, respectively) and the soleus muscle was measured pre- and postdenervation. Resistance arterioles from these muscles were removed, and dose responses to α1-phenylephrine or α2-clonidine adrenoreceptor agonists were determined with and without the vascular endothelium. Denervation resulted in a 2.7-fold increase in blood flow to the soleus and GastRed and an 8.7-fold increase in flow to the GastWhite. In isolated arterioles, α2-mediated vasoconstriction was greatest in GastWhite (∼50%) and less in GastRed (∼31%) and soleus (∼17%); differences among arterioles were abolished with the removal of the endothelium. There was greater sensitivity to α1-mediated vasoconstriction in the GastWhite and GastRed vs. the soleus, which was independent of whether the endothelium was present. These data indicate that 1) control of vascular resistance by the SNS in high-oxidative, fast-twitch muscle is intermediate to that of low-oxidative, fast-twitch and high-oxidative, slow-twitch muscles; and 2) the ability of the SNS to control blood flow to low-oxidative type IIB muscle appears to be mediated through postsynaptic α1- and α2-adrenoreceptors on the vascular smooth muscle.

scholarly journals Age-Related Changes in Molecular and Whole Muscle Function: Role of Fat Content?

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 141-141
Author(s):  
Joseph Gordon III ◽  
Nicholas Remillard ◽  
Chad Straight ◽  
Rajakumar Nagarajan ◽  
Bruce Damon ◽  
...  
Keyword(s):  
Older Adults ◽  
Molecular Mechanisms ◽  
Fat Content ◽  
Fat Deposition ◽  
Muscle Size ◽  
Type I ◽  
Contraction Velocity ◽  
Age Related ◽  
Whole Muscle ◽  
Age Related Changes

Abstract Decreases in muscle size and function are a general consequence of old age; the precise mechanisms of these changes remain unclear. Recent studies suggest that fat deposition in muscle may also contribute to dysfunction in older adults. Fat content was quantified in the quadriceps, and its effects on function in healthy young (21-45 y) and older (65-75 y) men and women (n=44) of comparable physical activity were compared. A subset of the young matched with the older group for muscle fat content were also examined. Peak fat-free whole muscle cross-sectional area (mCSA; cm2), volume (MV; cm3), fat content (fat fraction, FF; %), specific torque (Nm/mCSA) and peak contraction velocity (Nm∙s-1) were determined using fat-water magnetic resonance imaging and dynamometry (0-300□∙s-1). To examine potential molecular mechanisms of muscle weakness, vastus lateralis biopsies were obtained (n=31) and cross-bridge kinetics of type I and II fibers were determined. FF was higher in older adults than young (8.4±1.2% (SE), 7.6±1.4; p=0.03), while mCSA (48.9±10.4 vs. 64.2±17.3), MV (1536±532 vs. 2112±708), specific torque (2.6±0.4 vs. 3.2±0.4), and peak voluntary contraction velocity (422±20 vs. 441±23) were lower in older than young (p&lt;0.01). Type II fiber myosin attachment rate was slower and attachment time longer in older muscle (p&lt;0.017), providing a potential mechanism for the slowing of peak contraction velocity with age. Notably, differences at the whole muscle and molecular levels remained for the subset of young and older groups matched for FF, suggesting that fat deposition in muscle does not exacerbate age-related changes in function.

Differential scanning calorimetric study of the thermal unfolding of the motor domain fragments of Dictyostelium discoideum myosin II

1998 ◽  
Vol 251 (1-2) ◽  
pp. 275-280 ◽  
Author(s):  
Dmitrii I. Levitsky ◽  
Michael A. Ponomarev ◽  
Michael A. Geeves ◽  
Valery L. Shnyrov ◽  
Dietmar J. Manstein
Keyword(s):  
Dictyostelium Discoideum ◽  
Myosin Ii ◽  
Motor Domain ◽  
Thermal Unfolding ◽  
Differential Scanning Calorimetric ◽  
Calorimetric Study

scholarly journals Coiled-coil 1-mediated fastening of the neck and motor domains for kinesin-3 autoinhibition

2018 ◽  
Vol 115 (51) ◽  
pp. E11933-E11942 ◽  
Author(s):  
Jinqi Ren ◽  
Shuang Wang ◽  
Han Chen ◽  
Wenjuan Wang ◽  
Lin Huo ◽  
...  
Keyword(s):  
Coiled Coil ◽  
Underlying Mechanism ◽  
Motor Domain ◽  
Dimer Formation ◽  
Interaction Interface ◽  
Adp Release ◽  
Interdomain Interaction ◽  
Neck Domain ◽  
Neck Coil

In kinesin-3, the coiled-coil 1 (CC1) can sequester the preceding neck coil (NC) for autoinhibition, but the underlying mechanism is poorly understood. Here, we determined the structures of the uninhibited motor domain (MD)-NC dimer and inhibited MD-NC-CC1 monomer of kinesin-3 KIF13B. In the MD-NC-CC1 monomer, CC1 is broken into two short helices that unexpectedly interact with both the NC and the MD. Compared with the MD-NC dimer, the CC1-mediated integration of NC and MD not only blocks the NC dimer formation, but also prevents the neck linker (NL) undocking and the ADP release from the MD. Mutations of the essential residues in the interdomain interaction interface in the MD-NC-CC1 monomer restored the MD activity. Thus, CC1 fastens the neck domain and MD and inhibits both NC and NL. This CC1-mediated lockdown of the entire neck domain may represent a paradigm for kinesin autoinhibition that could be applicable to other kinesin-3 motors.

Cardiovascular changes in the exercising emu

1983 ◽  
Vol 104 (1) ◽  
pp. 193-201 ◽  
Author(s):  
B. Grubb ◽  
D. D. Jorgensen ◽  
M. Conner
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Oxygen Content ◽  
Body Mass ◽  
Fold Increase ◽  
Exercise Heart Rate ◽  
Rate Of Oxygen Consumption ◽  
Cardiovascular Variables

Cardiovascular variables were studied as a function of oxygen consumption in the emu, a large, flightless ratite bird well suited to treadmill exercise. At the highest level of exercise, the birds' rate of oxygen consumption (VO2) was approximately 11.4 times the resting level (4.2 ml kg-1 min-1). Cardiac output was linearly related to VO2, increasing 9.5 ml for each 1 ml increase in oxygen consumption. The increase in cardiac output is similar to that in other birds, but appears to be larger than in mammals. The venous oxygen content dropped during exercise, thus increasing the arteriovenous oxygen content difference. At the highest levels of exercise, heart rate showed a 3.9-fold increase over the resting rate (45.8 beats min-1). The mean resting specific stroke volume was 1.5 ml per kg body mass, which is larger than shown by most mammals. However, birds have larger hearts relative to body mass than do mammals, and stroke volume expressed per gram of heart (0.18 ml g-1) is similar to that for mammals. Stroke volume showed a 1.8-fold increase as a result of exercise in the emus, but a change in heart rate plays a greater role in increasing cardiac output during exercise.

Sign in / Sign up

Export Citation Format

Share Document