scholarly journals Expression of smooth muscle myosin heavy chains and unloaded shortening in single smooth muscle cells

1997 ◽  
Vol 273 (4) ◽  
pp. C1259-C1266 ◽  
Author(s):  
Daniel P. Meer ◽  
Thomas J. Eddinger
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Polymerase Chain Reaction Amplification ◽  
Mrna Level ◽  
Muscle Cells ◽  
Smooth Muscle Myosin ◽  
Minimum Length ◽  
Shortening Velocity ◽  
Variable Expression ◽  
Muscle Myosin

The functional significance of the variable expression of the smooth muscle myosin heavy chain (SM-MHC) tail isoforms, SM1 and SM2, was examined at the mRNA level (which correlates with the protein level) in individual permeabilized rabbit arterial smooth muscle cells (SMCs). The length of untethered single permeabilized SMCs was monitored during unloaded shortening in response to increased Ca2+ (pCa 6.0), histamine (1 μM), and phenylephrine (1 μM). Subsequent to contraction, the relative expression of SM1 and SM2 mRNAs from the same individual SMCs was determined by reverse transcription-polymerase chain reaction amplification and densitometric analysis. Correlational analyses between the SM2-to-SM1 ratio and unloaded shortening in saponin- and α-toxin-permeabilized SMCs ( n = 28) reveal no significant relationship between the SM-MHC tail isoform ratio and unloaded shortening velocity. The best correlations between SM2/SM1 and the contraction characteristics of untethered vascular SMCs were with the minimum length attained following contraction ( n = 20 and r = 0.72 for α-toxin, n = 8 and r = 0.78 for saponin). These results suggest that the primary effect of variable expression of the SM1 and SM2 SM-MHC tail isoforms is on the cell final length and not on shortening velocity.

scholarly journals Assembly of Smooth Muscle Myosin by the 38k Protein, a Homologue of a Subunit of Pre-mRNA Splicing Factor-2

2000 ◽  
Vol 148 (4) ◽  
pp. 653-664 ◽  
Author(s):  
Tsuyoshi Okagaki ◽  
Akio Nakamura ◽  
Tomohiko Suzuki ◽  
Kazuhiro Ohmi ◽  
Kazuhiro Kohama
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Smooth Muscles ◽  
Muscle Cells ◽  
Smooth Muscle Myosin ◽  
Mrna Splicing ◽  
Splicing Factor ◽  
A Subunit ◽  
Myosin Binding ◽  
Muscle Myosin

Smooth muscle myosin in the dephosphorylated state does not form filaments in vitro. However, thick filaments, which are composed of myosin and myosin-binding protein(s), persist in smooth muscle cells, even if myosin is subjected to the phosphorylation– dephosphorylation cycle. The characterization of telokin as a myosin-assembling protein successfully explained the discrepancy. However, smooth muscle cells that are devoid of telokin have been observed. We expected to find another ubiquitous protein with a similar role, and attempted to purify it from chicken gizzard. The 38k protein bound to both phosphorylated and dephosphorylated myosin to a similar extent. The effect of the myosin-binding activity was to assemble dephosphorylated myosin into filaments, although it had no effect on the phosphorylated myosin. The 38k protein bound to myosin with both COOH-terminal 20 and NH2-terminal 28 residues of the 38k protein being essential for myosin binding. The amino acid sequence of the 38k protein was not homologous to telokin, but to human p32, which was originally found in nuclei as a subunit of pre-mRNA splicing factor-2. Western blotting showed that the protein was expressed in various smooth muscles. Immunofluorescence microscopy with cultured smooth muscle cells revealed colocalization of the 38k protein with myosin and with other cytoskeletal elements. The absence of nuclear immunostaining was discussed in relation to smooth muscle differentiation.

Expression of smooth muscle myosin in relation to growth kinetics of cultured aortic smooth muscle cells

1988 ◽  
Vol 178 (2) ◽  
pp. 390-400 ◽  
Author(s):  
H. Hammerle ◽  
J. Fingerle ◽  
J. Rupp ◽  
J. Grünwaldt ◽  
E. Betz ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Growth Kinetics ◽  
Muscle Cells ◽  
Smooth Muscle Myosin ◽  
Aortic Smooth Muscle Cells ◽  
Aortic Smooth Muscle ◽  
Muscle Myosin ◽  
Kinetics Of

Age dependence of smooth muscle myosin expression by cultured rat aortic smooth muscle cells

1999 ◽  
Vol 65 (3) ◽  
pp. 151-159 ◽  
Author(s):  
Robert B. Low ◽  
Sheryl L. White ◽  
Elizabeth S. Low ◽  
Pascal Neuville ◽  
Marie-Luce Bochaton-Piallat ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Smooth Muscle Myosin ◽  
Age Dependence ◽  
Aortic Smooth Muscle Cells ◽  
Aortic Smooth Muscle ◽  
Muscle Myosin

scholarly journals Smitin, a novel smooth muscle titin–like protein, interacts with myosin filaments in vivo and in vitro

2002 ◽  
Vol 156 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Kyoungtae Kim ◽  
Thomas C.S. Keller
Keyword(s):  
Smooth Muscle ◽  
Ionic Strength ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Smooth Muscle Myosin ◽  
Globular Domain ◽  
Contractile Apparatus ◽  
Myosin Filaments ◽  
Muscle Myosin

Smooth muscle cells use an actin–myosin II-based contractile apparatus to produce force for a variety of physiological functions, including blood pressure regulation and gut peristalsis. The organization of the smooth muscle contractile apparatus resembles that of striated skeletal and cardiac muscle, but remains much more poorly understood. We have found that avian vascular and visceral smooth muscles contain a novel, megadalton protein, smitin, that is similar to striated muscle titin in molecular morphology, localization in a contractile apparatus, and ability to interact with myosin filaments. Smitin, like titin, is a long fibrous molecule with a globular domain on one end. Specific reactivities of an anti-smitin polyclonal antibody and an anti-titin monoclonal antibody suggest that smitin and titin are distinct proteins rather than differentially spliced isoforms encoded by the same gene. Smitin immunofluorescently colocalizes with myosin in chicken gizzard smooth muscle, and interacts with two configurations of smooth muscle myosin filaments in vitro. In physiological ionic strength conditions, smitin and smooth muscle myosin coassemble into irregular aggregates containing large sidepolar myosin filaments. In low ionic strength conditions, smitin and smooth muscle myosin form highly ordered structures containing linear and polygonal end-to-end and side-by-side arrays of small bipolar myosin filaments. We have used immunogold localization and sucrose density gradient cosedimentation analyses to confirm association of smitin with both the sidepolar and bipolar smooth muscle myosin filaments. These findings suggest that the titin-like protein smitin may play a central role in organizing myosin filaments in the contractile apparatus and perhaps in other structures in smooth muscle cells.

Microvessel precursor smooth muscle cells express head-inserted smooth muscle myosin heavy chain (SM-B) isoform in hyperoxic

1999 ◽  
Vol 295 (3) ◽  
pp. 453-465 ◽  
Author(s):  
R. Jones ◽  
Wolfgang Steudel ◽  
Sheryl White ◽  
Margaretha Jacobson ◽  
Robert Low
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Muscle Cells ◽  
Smooth Muscle Myosin ◽  
Muscle Myosin

scholarly journals Lipid Lowering Promotes Accumulation of Mature Smooth Muscle Cells Expressing Smooth Muscle Myosin Heavy Chain Isoforms in Rabbit Atheroma

1998 ◽  
Vol 83 (10) ◽  
pp. 1015-1026 ◽  
Author(s):  
Masanori Aikawa ◽  
Elena Rabkin ◽  
Sami J. Voglic ◽  
Helen Shing ◽  
Ryozo Nagai ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Muscle Cells ◽  
Myosin Heavy Chain Isoforms ◽  
Smooth Muscle Myosin ◽  
Lipid Lowering ◽  
Muscle Myosin

Blebbistatin inhibits the chemotaxis of vascular smooth muscle cells by disrupting the myosin II-actin interaction

2008 ◽  
Vol 294 (5) ◽  
pp. H2060-H2068 ◽  
Author(s):  
Hong Hui Wang ◽  
Hideyuki Tanaka ◽  
Xiaoran Qin ◽  
Tiejun Zhao ◽  
Li-Hong Ye ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Myosin Ii ◽  
Muscle Cells ◽  
Smooth Muscle Myosin ◽  
A7r5 Cells ◽  
Microscopic Evaluation ◽  
Muscle Myosin

Blebbistatin is a myosin II-specific inhibitor. However, the mechanism and tissue specificity of the drug are not well understood. Blebbistatin blocked the chemotaxis of vascular smooth muscle cells (VSMCs) toward sphingosylphosphorylcholine (IC50 = 26.1 ± 0.2 and 27.5 ± 0.5 μM for GbaSM-4 and A7r5 cells, respectively) and platelet-derived growth factor BB (IC50 = 32.3 ± 0.9 and 31.6 ± 1.3 μM for GbaSM-4 and A7r5 cells, respectively) at similar concentrations. Immunofluorescence and fluorescent resonance energy transfer analysis indicated a blebbistatin-induced disruption of the actin-myosin interaction in VSMCs. Subsequent experiments indicated that blebbistatin inhibited the Mg2+-ATPase activity of the unphosphorylated (IC50 = 12.6 ± 1.6 and 4.3 ± 0.5 μM for gizzard and bovine stomach, respectively) and phosphorylated (IC50 = 15.0 ± 0.6 μM for gizzard) forms of purified smooth muscle myosin II, suggesting a direct effect on myosin II motor activity. It was further observed that the Mg2+-ATPase activities of gizzard myosin II fragments, heavy meromyosin (IC50 = 14.4 ± 1.6 μM) and subfragment 1 (IC50 = 5.5 ± 0.4 μM), were also inhibited by blebbistatin. Assay by in vitro motility indicated that the inhibitory effect of blebbistatin was reversible. Electron-microscopic evaluation showed that blebbistatin induced a distinct conformational change (i.e., swelling) of the myosin II head. The results suggest that the site of blebbistatin action is within the S1 portion of smooth muscle myosin II.

scholarly journals Nonmuscle Myosin Motor of Smooth Muscle

2003 ◽  
Vol 121 (4) ◽  
pp. 301-310 ◽  
Author(s):  
Mia Löfgren ◽  
Eva Ekblad ◽  
Ingo Morano ◽  
Anders Arner
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Calcium Handling ◽  
Nonmuscle Myosin ◽  
Phosphate Binding ◽  
Shortening Velocity ◽  
Heavy Chains ◽  
The Difference ◽  
Muscle Myosin

Nonmuscle myosin can generate force and shortening in smooth muscle, as revealed by studies of the urinary bladder from mice lacking smooth muscle myosin heavy chain (SM-MHC) but expressing the nonmuscle myosin heavy chains A and B (NM-MHC A and B; Morano, I., G.X. Chai, L.G. Baltas, V. Lamounier-Zepter, G. Lutsch, M. Kott, H. Haase, and M. Bader. 2000. Nat. Cell Biol. 2:371–375). Intracellular calcium was measured in urinary bladders from SM-MHC–deficient and SM-MHC–expressing mice in relaxed and contracted states. Similar intracellular [Ca2+] transients were observed in the two types of preparations, although the contraction of SM-MHC–deficient bladders was slow and lacked an initial peak in force. The difference in contraction kinetics thus do not reflect differences in calcium handling. Thick filaments were identified with electron microscopy in smooth muscle cells of SM-MHC–deficient bladders, showing that NM-MHC can form filaments in smooth muscle cells. Maximal shortening velocity of maximally activated, skinned smooth muscle preparations from SM-MHC–deficient mice was significantly lower and more sensitive to increased MgADP compared with velocity of SM-MHC–expressing preparations. Active force was significantly lower and less inhibited by increased inorganic phosphate. In conclusion, large differences in nucleotide and phosphate binding exist between smooth and nonmuscle myosins. High ADP binding and low phosphate dependence of nonmuscle myosin would influence both velocity of actin translocation and force generation to promote slow motility and economical force maintenance of the cell.

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