scholarly journals Human atrial and ventricular myosin light-chains subunits in the adult and during development

1980 ◽  
Vol 191 (2) ◽  
pp. 571-580 ◽  
Author(s):  
K M Price ◽  
W A Littler ◽  
P Cummins
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Ventricular Myocardium ◽  
Postnatal Period ◽  
Two Dimensional ◽  
Human Right ◽  
Stage Of Development ◽  
The Right ◽  
Ventricular Myosin Light Chains ◽  
Dimensional Electrophoresis

1. Myosin was isolated from human right- and left-atrial and -ventricular myocardium, and examined both in adult subjects and at different stages during pre- and post-natal development. 2. The myosin light-chain subunits in the atria and ventricles were different when characterized by isoelectric focusing and subsequent two-dimensional poly-acrylamide-gel electrophoresis. 3. No differences were observed between the light-chain subunits in the right and left ventricle at any stage of development. 4. The foetal ventricle contained a characteristic light chain that was a major component throughout the latter half of gestation. This foetal light chain, which disappeared in the postnatal period, could not be distinguished from adult atrial light chain 1 on two-dimensional electrophoresis. 5. Myosin in the adult atria, particularly the left, contained components similar to ventricular light-chain components. 6. The possible stimuli for the observed changes in myosin light-chain expression are discussed in relation to the known physiological changes occurring during development.

Contrasting inotropic responses to α1-adrenergic receptor stimulation in left versus right ventricular myocardium

2006 ◽  
Vol 291 (4) ◽  
pp. H2013-H2017 ◽  
Author(s):  
Guan-Ying Wang ◽  
Diana T. McCloskey ◽  
Sally Turcato ◽  
Philip M. Swigart ◽  
Paul C. Simpson ◽  
...  
Keyword(s):  
Light Chain ◽  
Adrenergic Receptor ◽  
Myosin Light Chain ◽  
Kinase Inhibitor ◽  
Ventricular Myocardium ◽  
Differential Activation ◽  
Kinase C ◽  
Pkc Isoforms ◽  
Myofilament Function ◽  
Inotropic Responses

The left ventricle (LV) and right ventricle (RV) have differing hemodynamics and embryological origins, but it is unclear whether they are regulated differently. In particular, no previous studies have directly compared the LV versus RV myocardial inotropic responses to α1-adrenergic receptor (α1-AR) stimulation. We compared α1-AR inotropy of cardiac trabeculae from the LV versus RV of adult mouse hearts. As previously reported, for mouse RV trabeculae, α1-AR stimulation with phenylephrine (PE) caused a triphasic contractile response with overall negative inotropy. In marked contrast, LV trabeculae had an overall positive inotropic response to PE. Stimulation of a single subtype (α1A-AR) with A-61603 also mediated contrasting LV/RV inotropy, suggesting differential activation of multiple α1-AR-subtypes was not involved. Contrasting LV/RV α1-AR inotropy was not abolished by inhibiting protein kinase C, suggesting differential activation of PKC isoforms was not involved. However, contrasting LV/RV α1-AR inotropic responses did involve different effects on myofilament Ca2+ sensitivity: submaximal force of skinned trabeculae was increased by PE pretreatment for LV but was decreased by PE for RV. For LV myocardium, α1-AR-induced net positive inotropy was abolished by the myosin light chain kinase inhibitor ML-9. This study suggests that LV and RV myocardium have fundamentally different inotropic responses to α1-AR stimulation, involving different effects on myofilament function and myosin light chain phosphorylation.

Inhibition of myosin light chain phosphatase during Ca(2+)-independent vasocontraction

1993 ◽  
Vol 265 (5) ◽  
pp. C1319-C1324 ◽  
Author(s):  
H. Itoh ◽  
A. Shimomura ◽  
S. Okubo ◽  
K. Ichikawa ◽  
M. Ito ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Water Soluble ◽  
Two Dimensional ◽  
Kinase C ◽  
Rat Thoracic Aorta ◽  
Phosphopeptide Mapping

Phorbol 12,13-dibutyrate (PDB) induced a sustained contraction of rat thoracic aorta strip in Ca(2+)-free buffer without significant change in intracellular free Ca2+ concentration. NKH477, a water-soluble forskolin derivative, markedly relaxed the PDB-induced contraction. The PDB-induced contraction was associated with the phosphorylation of 20-kDa myosin light chain (MLC). Two-dimensional phosphopeptide mapping of 20-kDa MLC revealed that approximately 90% of the phosphopeptides was derived from an MLC kinase-catalyzed reaction and approximately 10% was due to phosphorylation by protein kinase C. NKH477 inhibited the PDB-induced phosphorylation of 20-kDa MLC. MLC phosphatase activity of intact aorta strips was inhibited by the treatment with PDB, and the inhibition was recovered by the application of NKH477. These results suggest that the regulation of MLC phosphatase in vascular smooth muscle may play important roles in the PDB-induced contraction and the NKH477-induced relaxation in Ca(2+)-free buffer.

scholarly journals Regulation of expression of myosin light chain 1 in the overloading human left ventricular myocardium

1990 ◽  
Vol 52 ◽  
pp. 249
Author(s):  
Kazuteru Fujimoto ◽  
Koichi Nakao ◽  
Toyoaki Murohara ◽  
Ken Okumura ◽  
Yasuhiro Morikami ◽  
...  
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Regulation Of Expression

Two-dimensional electrophoretic analysis of myosin light chain phosphorylation in heart

1983 ◽  
Vol 4 (2) ◽  
pp. 138-142 ◽  
Author(s):  
Kate Bárány ◽  
Scott T. Sayers ◽  
Joseph Disalvo ◽  
Michael Bárány
Keyword(s):  
Light Chain ◽  
Myosin Light Chain ◽  
Electrophoretic Analysis ◽  
Myosin Light Chain Phosphorylation ◽  
Two Dimensional

scholarly journals Fast myosin light chain expression in chicken muscles studied by in situ hybridization.

1992 ◽  
Vol 40 (10) ◽  
pp. 1547-1557 ◽  
Author(s):  
R Billeter ◽  
M Messerli ◽  
E Wey ◽  
A Puntschart ◽  
K Jostarndt ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Fiber Type ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Two Dimensional ◽  
Fast Myosin ◽  
Chicken Muscles

We have studied the fiber type-specific expression of the fast myosin light chain isoforms LC 1f, LC 2f, and LC 3f in adult chicken muscles using in situ hybridization and two-dimensional gel electrophoresis. Type II (fast) fibers contain all three fast myosin light chain mRNAs; Types I and III (slow) fibers lack them. The myosin light chain patterns of two-dimensional gels from microdissected single fibers match their mRNA signals in the in situ hybridizations. The results confirm and extend previous studies on the fiber type-specific distribution of myosin light chains in chicken muscles which used specific antibodies. The quantitative ratios between protein and mRNA content were not the same for all three fast myosin light chains, however. In bulk muscle samples, as well as in single fibers, there was proportionally less LC 3f accumulated for a given mRNA concentration than LC 1f or LC 2f. Moreover, the ratio between LC 3f mRNA and protein was different in samples from muscles, indicating that LC 3f is regulated somewhat differently than LC 1f and LC 2f. In contrast to other in situ hybridization studies on the fiber type-specific localization of muscle protein mRNAs, which reported the RNAs to be located preferentially at the periphery of the fibers, we found all three fast myosin light chain mRNAs quite evenly distributed within the fiber's cross-sections, and also in the few rare fibers which showed hybridization signals several-fold higher than their surrounding counterparts. This could indicate principal differences in the intracellular localization among the mRNAs coding for various myofibrillar protein families.

Endurance training-induced changes in alkali light chain patterns in type IIB fibers of the rat

2003 ◽  
Vol 94 (3) ◽  
pp. 923-929 ◽  
Author(s):  
Masanobu Wada ◽  
Shuichiro Inashima ◽  
Takashi Yamada ◽  
Satoshi Matsunaga
Keyword(s):  
Endurance Training ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Vastus Lateralis Muscle ◽  
Lateralis Muscle ◽  
Induced Changes ◽  
Whole Muscle ◽  
Dimensional Electrophoresis

The effects of endurance training on the expression of myosin were electrophoretically analyzed in the deep portion of vastus lateralis muscle from the rat. A 10-wk running program led to increases ( P < 0.01) in myosin heavy chain (MHC) 2a and 2d with a decrease ( P < 0.01) in MHC2b. Training also evoked a rearrangement of the isomyosin pattern with decreases in fast isomyosin (FM) 1 ( P < 0.01) and FM2 ( P < 0.05) and a rise in intermediate isomyosin ( P < 0.01). These changes were accompanied by a 61% decrease ( P < 0.01) in myosin light chain (MLC) 3F (11.8 ± 2.7 vs. 4.6 ± 4.2%). Two-dimensional electrophoresis made it possible to separate the triplet of isomyosins (FMb) consisting of MHC2b. Training elicited a 26% decrease ( P < 0.05) in the FM1b fraction within FMb, i.e., FM1b/(FM1b + FM2b + FM3b) (24.2 ± 5.5 vs. 18.0 ± 4.3%). These changes resulted in a 10% decrease ( P < 0.05) in the MLC3Ffraction, i.e., MLC3F/(MLC1F + MLC3F), in FMb (44.9 ± 4.5 vs. 40.3 ± 3.2%). These results suggest that endurance training may exert the depressive effect on the contractile velocity of type IIB fibers and that a training-induced decrease in the contractile velocity of whole muscle may be caused by alterations in fast alkali MLC complements within a given fiber type as well as by transitions in MHC-based fiber populations.

scholarly journals Loss of fast-twitch isomyosins in skeletal muscles of the diabetic rat

1984 ◽  
Vol 221 (3) ◽  
pp. 645-650 ◽  
Author(s):  
M Rutschmann ◽  
B Dahlmann ◽  
H Reinauer
Keyword(s):  
Diabetes Mellitus ◽  
Light Chain ◽  
Skeletal Muscles ◽  
Diabetic Rat ◽  
Two Dimensional ◽  
Two Dimensional Electrophoresis ◽  
Slow Twitch ◽  
Normal Light ◽  
Fast Twitch ◽  
Dimensional Electrophoresis

By means of pyrophosphate electrophoresis the myosin isoenzyme pattern of two fast-twitch skeletal muscles (extensor digitorum longus, gastrocnemius) and one slow-twitch muscle (soleus) was investigated in control rats and was compared with that of rats 4 weeks after induction of diabetes mellitus by streptozotocin injection. In the fast-twitch muscles the isomyosin pattern consisting of FM1 (fast isomyosin 1), FM2 and FM3 was strongly affected by diabetes, resulting in an extensive loss of FM1 and a substantial decrease of FM2. These changes were also apparent when the light chains of the fast isomyosins were analysed by two-dimensional electrophoresis: LC3f (myosin light chain 3f) largely disappeared and LC2f was significantly diminished. In contrast, the isomyosin pattern in soleus muscle, consisting of SM1 (slow isomyosin 1) and SM2, was not affected by the diabetic state, and two-dimensional electrophoresis revealed a normal light-chain pattern of LC1sa, LC1sb and LC2s. These results indicate that the isomyosins of slow-twitch oxidative myofibres are more resistant to the hormonal and metabolic disorders during diabetes mellitus than are the isomyosins of fast-twitch fibres.

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