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Tytuł:
Reconstitution of ventricular myosin with atrial light chains 1 improves its functional properties.
Autorzy:
Khalina, Yana
Bartsch, Holger
Petzhold, Daria
Haase, Hannelore
Podlubnaya, Zoya
Shpagina, Mila
Morano, Ingo
Powiązania:
https://bibliotekanauki.pl/articles/1041425.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
myosin light chains
cardiac myosin
dilated cardiomyopathy
myosin filaments
reconstituted myosin
actin-activated ATPase activity
Opis:
Atrial light chain 1 (ALC-1) is expressed in embryonic and hypertrophied human ventricles but not in normal adult human ventricles. We investigated the effects of recombinant human atrial light chains (hALC-1) on the structure and enzymatic activity of synthetic filaments of ventricular myosin. The endogenous ventricular myosin light chain 1 (VLC-1) was partially replaced by recombinant hALC-1 yielding hALC-1 levels of 12%, 24% and 42%. This reconstitution of ventricular myosin with hALC-1 did not change the length of synthetic myosin filaments but led to more rounded myosin heads in comparison with those of control filaments. Actin-activated ATPase activity of myosin, a parameter of functional activity of molecular motor, amounted to 79.5 nmol Pi/mg per min in control myosin filaments. Reconstitution with hALC-1 caused a profound increase of the actin-activated myosin ATPase activity in a dose dependent manner, for example, synthetic myosin filaments formed with 12%, 24% and 42% hALC-1 reconstituted myosin revealed the actin-activated ATPase activity increased by 18%, 26% and 36%, respectively, as compared to control. These results strongly suggest that in vivo expression of ALC-1 enhances ventricular myosin function, thereby contributing to cardiac compensation.
Źródło:
Acta Biochimica Polonica; 2005, 52, 2; 443-448
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Order-disorder structural transitions in synthetic filaments of fast and slow skeletal muscle myosins under relaxing and activating conditions.
Autorzy:
Podlubnaya, Zoya
Malyshev, Sergey
Nieznański, Krzysztof
Stępkowski, Dariusz
Powiązania:
https://bibliotekanauki.pl/articles/1044221.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
method of slow skeletal muscle myosin preparation.
Ca2+-induced structural transitions
myosin filaments
fast and slow skeletal muscle myosin
Opis:
In the previous study (Podlubnaya et al., 1999, J. Struc. Biol. 127, 1-15) Ca2+-induced reversible structural transitions in synthetic filaments of pure fast skeletal and cardiac muscle myosins were observed under rigor conditions (-Ca2+/+ Ca2+). In the present work these studies have been extended to new more order-producing conditions (presence of ATP in the absence of Ca2+) aimed at arresting the relaxed structure in synthetic filaments of both fast and slow skeletal muscle myosin. Filaments were formed from column-purified myosins (rabbit fast skeletal muscle and rabbit slow skeletal semimebranosus proprius muscle). In the presence of 0.1 mM free Ca2+, 3 mM Mg2+ and 2 mM ATP (activating conditions) these filaments had a spread structure with a random arrangement of myosin heads and subfragments 2 protruding from the filament backbone. Such a structure is indistinguishable from the filament structures observed previously for fast skeletal, cardiac (see reference cited above) and smooth (Podlubnaya et al., 1999, J. Muscle Res. Cell Motil. 20, 547-554) muscle myosins in the presence of 0.1 mM free Ca2+. In the absence of Ca2+ and in the presence of ATP (relaxing conditions) the filaments of both studied myosins revealed a compact ordered structure. The fast skeletal muscle myosin filaments exhibited an axial periodicity of about 14.5 nm and which was much more pronounced than under rigor conditions in the absence of Ca2+ (see the first reference cited). The slow skeletal muscle myosin filaments differ slightly in their appearance from those of fast muscle as they exhibit mainly an axial repeat of about 43 nm while the 14.5 nm repeat is visible only in some regions. This may be a result of a slightly different structural properties of slow skeletal muscle myosin. We conclude that, like other filaments of vertebrate myosins, slow skeletal muscle myosin filaments also undergo the Ca2+-induced structural order-disorder transitions. It is very likely that all vertebrate muscle myosins possess such a property.
Źródło:
Acta Biochimica Polonica; 2000, 47, 4; 1007-1017
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new method to precipitate myosin v from rat brain soluble fraction
Autorzy:
Melo, Hugo
Coelho, Milton
Powiązania:
https://bibliotekanauki.pl/articles/1041042.pdf
Data publikacji:
2007
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
myosin V
ATPase
F-actin
Opis:
Myosin can be precipitated from soluble fraction under different assay conditions. This paper describes a new method for precipitating myosin V from rat brain soluble fraction. Brains were homogenized in 50 mM imidazole/HCl buffer, pH 8.0, containing 10 mM EDTA/EGTA, 250 mM sucrose, 1 mM DTT and 1 mM benzamidine, centrifuged at 45000 × g for 40 min and the supernatant was frozen at -20 °C. Forty-eight hours later, the supernatant was thawed, centrifuged at 45000 × g for 40 min and the precipitate was washed in 20 mM imidazole buffer pH 8.0. SDS/PAGE analysis showed four polypeptides in the precipitate: 205, 150, 57 and 43 kDa. The precipitate presented high Mg2+-ATPase activity, which co-purifies with p205. This polypeptide was recognized by a specific myosin V antibody and was proteolised by calpain, generating two stable polypeptides: p130 and p90. The Mg2+-ATPase activity was not stimulated by calcium in both the absence and presence of exogenous calmodulin and the K+/EDTA-ATPase activity represented 25% of the Mg2+-ATPase activity. In this work, myosin V from rat brain was precipitated by freezing the soluble fraction and was co-purificated with a 45 kDa polypeptide.
Źródło:
Acta Biochimica Polonica; 2007, 54, 3; 575-581
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Myosins and pathology: genetics and biology.
Autorzy:
Rędowicz, Maria
Powiązania:
https://bibliotekanauki.pl/articles/1043680.pdf
Data publikacji:
2002
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
vision
cardiomyopathy
myosin
pathology
deafness
Opis:
This article summarizes current knowledge on the genetics and possible molecular mechanisms of human pathologies resulted from mutations within the genes encoding several myosin isoforms. Mutations within the genes encoding some myosin isoforms have been found to be responsible for blindness (myosins III and VIIA), deafness (myosins I, IIA, IIIA, VI, VIIA and XV) and familial hypertrophic cardiomyopathy (β cardiac myosin heavy chain and both the regulatory and essential light chains). Myosin III localizes predominantly to photoreceptor cells and is proved to be engaged in the vision process in Drosophila. In the inner ear, myosin I is postulated to play a role as an adaptive motor in the tip links of stereocilia of hair cells, myosin IIA seems to be responsible for stabilizing the contacts between adjacent inner ear hair cells, myosin VI plays a role as an intracellular motor transporting membrane structures within the hair cells while myosin VIIA most probably participates in forming links between neighbouring stereocilia and myosin XV probably stabilizes the stereocilia structure. About 30% of patients with familial hypertrophic cardiomyopathy have mutations within the genes encoding the β cardiac myosin heavy chain and both light chains that are grouped within the regions of myosin head crucial for its functions. The alterations lead to the destabilization of sarcomeres and to a decrease of the myosin ATPase activity and its ability to move actin filaments.
Źródło:
Acta Biochimica Polonica; 2002, 49, 4; 789-804
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural determinants of cooperativity in acto-myosin interactions.
Autorzy:
Moraczewska, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/1043682.pdf
Data publikacji:
2002
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
cooperativity
acto-myosin regulation
tropomyosin
contraction
Opis:
Regulation of muscle contraction is a very cooperative process. The presence of tropomyosin on the thin filament is both necessary and sufficient for cooperativity to occur. Data recently obtained with various tropomyosin isoforms and mutants help us to understand better the structural requirements in the thin filament for cooperative protein interactions. Forming an end-to-end overlap between neighboring tropomyosin molecules is not necessary for the cooperativity of the thin filament activation. When direct contacts between tropomyosin molecules are disrupted, the conformational changes in the filament are most probably transmitted cooperatively through actin subunits, although the exact nature of these changes is not known. The function of tropomyosin ends, alternatively expressed in various isoforms, is to confer specific actin affinity. Tropomyosin's affinity or actin is directly related to the size of the apparent cooperative unit defined as the number of actin subunits turned into the active state by binding of one myosin head. Inner sequences of tropomyosin, particularly actin-binding periods 3 to 5, play crucial role in myosin-induced activation of the thin filament. A plausible mechanism of tropomyosin function in this process is that inner tropomyosin regions are either specifically recognized by myosin or they define the right actin conformation required for tropomyosin movement from its blocking position.
Źródło:
Acta Biochimica Polonica; 2002, 49, 4; 805-812
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The slow sarco/endoplasmic reticulum Ca2+-ATPase declines independently of slow myosin in soleus muscle of diabetic rats
Autorzy:
Rácz, Gábor
Szabó, András
Vér, Ágota
Zádor, Ernő
Powiązania:
https://bibliotekanauki.pl/articles/1040545.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
muscle fibers
myosin
SERCA
diabetic rat
Opis:
The sarcoplasmic reticulum Ca2+-ATPase (SERCA) isoforms are normally expressed in coordination with the corresponding myosin heavy chain (MyHC) isoforms in the fibers of skeletal muscle but this coordination is often disrupted in pathological conditions. In the streptozotocin-induced diabetes of rats (stz-rats), the soleus muscle showed peripheral neuropathy and the SERCA2a level decreased in type I (slow-oxidative) fibers compared to the control muscles, whereas the expression of the corresponding slow MyHC1 did not change. No difference was found at the mRNA and protein levels of SERCA and MyHC isoforms in the whole soleus, except that the level of the SERCA2a protein specifically declined in stz-rats compared to the controls. This shows that the coordinated expression of SERCA2a and MyHC1 is disrupted at the SERCA2a protein level in the diabetic soleus. The results are in line with previous observations that regulators of the Ca-homeostasis may adapt faster to type I diabetes than the contractile elements.
Źródło:
Acta Biochimica Polonica; 2009, 56, 3; 487-493
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structure, function, and regulation of myosin 1C.
Autorzy:
Barylko, Barbara
Jung, Gwanghyun
Albanesi, Joseph
Powiązania:
https://bibliotekanauki.pl/articles/1041416.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
myosin 1
membrane protein translocation
domain structure
Opis:
Myosin 1C, the first mammalian single-headed myosin to be purified, cloned, and sequenced, has been implicated in the translocation of plasma membrane channels and transporters. Like other forms of myosin I (of which eight exist in humans) myosin 1C consists of motor, neck, and tail domains. The neck domain binds calmodulins more tightly in the absence than in the presence of Ca^(2+). Release of calmodulins exposes binding sites for anionic lipids, particularly phosphoinositides. The tail domain, which has an isoelectic point of 10.5, interacts with anionic lipid headgroups. When both neck and tail lipid binding sites are engaged, the myosin associates essentially irreversibly with membranes. Despite this tight membrane binding, it is widely believed that myosin 1C docking proteins are necessary for targeting the enzyme to specific subcellular location. The search for these putative myosin 1C receptors is an active area of research.
Źródło:
Acta Biochimica Polonica; 2005, 52, 2; 373-380
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Is MLC phosphorylation essential for the recovery from ROCK inhibition in glioma C6 cells?
Autorzy:
Korczyński, Jarosław
Sobierajska, Katarzyna
Krzemiński, Patryk
Wasik, Anna
Wypych, Dorota
Pomorski, Paweł
Kłopocka, Wanda
Powiązania:
https://bibliotekanauki.pl/articles/1039964.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
RhoA
myosin II
calcium signaling
actin
MLC phosphorylation
Opis:
Inhibition of Rho-associated protein kinase (ROCK) activity in glioma C6 cells induces changes in actin cytoskeleton organization and cell morphology similar to those observed in other types of cells with inhibited RhoA/ROCK signaling pathway. We show that phosphorylation of myosin light chains (MLC) induced by P2Y2 receptor stimulation in cells with blocked ROCK correlates in time with actin cytoskeleton reorganization, F-actin redistribution and stress fibers assembly followed by recovery of normal cell morphology. Presented results indicate that myosin light-chain kinase (MLCK) is responsible for the observed phosphorylation of MLC. We also found that the changes induced by P2Y2 stimulation in actin cytoskeleton dynamics and morphology of cells with inhibited ROCK, but not in the level of phosphorylated MLC, depend on the presence of calcium in the cell environment.
Źródło:
Acta Biochimica Polonica; 2011, 58, 1; 125-130
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Myosin VI is associated with secretory granules and is present in the nucleus in adrenal medulla chromaffin cells
Autorzy:
Majewski, Łukasz
Sobczak, Magdalena
Rędowicz, Maria
Powiązania:
https://bibliotekanauki.pl/articles/1040436.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
myosin VI
chromaffin granules
PC12 cells
Golgi apparatus
Opis:
Myosin VI (MVI) is the only known myosin walking towards minus end of actin filaments. Here, MVI, but not myosins IB or IIB, was detected in chromaffin granules isolated from bovine medulla and found to be tightly associated with the granule apical surface. MVI also localized to secretory granules within rat pheochromocytoma PC12 cells as well as to the Golgi apparatus, endoplasmic reticulum and clathrin-coated pits. Notably, it was also found in the nucleus. RT-PCR revealed that MVI splice variants with a large insert (LI), characteristic of polarized cells, were barely detectable in PC12 cells, whereas variants with a small insert (SI) were the major isoforms. The presented data indicate that MVI in adrenal medulla cells is engaged in secretory vesicle trafficking within the cytoplasm and possibly also involved in transport within the nucleus.
Źródło:
Acta Biochimica Polonica; 2010, 57, 1; 109-114
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Myosin molecule packing within the vertebrate skeletal muscle thick filaments. A complete bipolar model*
Autorzy:
Skubiszak, Ludmila
Kowalczyk, Leszek
Powiązania:
https://bibliotekanauki.pl/articles/1043686.pdf
Data publikacji:
2002
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
thick filament
computer modelling
myosin molecule packing
vertebrate skeletal muscle
cross-bridge action
Opis:
Computer modelling related to the real dimensions of both the whole filament and the myosin molecule subfragments has revealed two alternative modes for myosin molecule packing which lead to the head disposition similar to that observed by EM on the surface of the cross-bridge zone of the relaxed vertebrate skeletal muscle thick filaments. One of the modes has been known for three decades and is usually incorporated into the so-called three-stranded model. The new mode differs from the former one in two aspects: (1) myosin heads are grouped into asymmetrical cross-bridge crowns instead of symmetrical ones; (2) not the whole myosin tail, but only a 43-nm C-terminus of each of them is straightened and near-parallel to the filament axis, the rest of the tail is twisted. Concurrent exploration of these alternative modes has revealed their influence on the filament features. The parameter values for the filament models as well as for the building units depicting the myosin molecule subfragments are verified by experimental data found in the literature. On the basis of the new mode for myosin molecule packing a complete bipolar structure of the thick filament is created.
Źródło:
Acta Biochimica Polonica; 2002, 49, 4; 829-840
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
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