scholarly journals Differential actin isoform reorganization in the contracting A7r5 cell

2006 ◽  
Vol 20 (5) ◽  
Author(s):  
Dawn Leah Brown ◽  
Ava Dykes ◽  
Jason Black ◽  
Sean Thatcher ◽  
Mike Fultz ◽  
...  
Keyword(s):  
A7r5 Cell ◽  
Actin Isoform

Differential actin isoform reorganization in the contracting A7r5 cell

2006 ◽  
Vol 84 (8-9) ◽  
pp. 867-875 ◽  
Author(s):  
D. Brown ◽  
A. Dykes ◽  
J. Black ◽  
S. Thatcher ◽  
M.E. Fultz ◽  
...  
Keyword(s):  
Stress Fibers ◽  
Partial Loss ◽  
Cell Content ◽  
Cytoskeletal Structure ◽  
A7r5 Cell ◽  
Kinase C ◽  
Low Concentrations ◽  
Actin Isoform ◽  
High Concentrations ◽  
Actin Stress Fibers

In the present study, we investigated the reorganization of α- and β-actin in the contracting A7r5 smooth muscle cell. The remodeling of these actin variants was markedly different in response to increasing concentrations of phorbol 12, 13-dibutyrate (PDBu). At the lowest concentrations (≤10−7 mol/L), cells showed an ~70% loss in α-actin stress fibers with robust transport of this isoform to podosomes. By comparison, β-actin remained in stress fibers in cells stimulated at low concentrations (≤10−7 mol/L) of PDBu. However, at high concentrations (≥10−6 mol/L) ~50% of cells showed transport of β-actin to podosomes. Consistent with these findings, staining with phalloidin indicated a significant decrease in the whole-cell content of F-actin with PDBu treatment. However, staining with DNase I indicated no change in the cellular content of G-actin, suggesting reduced access of phalloidin to tightly packed actin in the podosome core. Inhibition of protein kinase C (staurosporine, bisindolymaleimide) blocked PDBu-induced (5 × 10−8 mol/L) loss in α-actin stress fibers or reversed podosome formation with re-establishment of α-actin stress fibers. By comparison, these inhibitors caused partial loss of β-actin stress fibers. The results support our earlier conclusion of independent remodeling of α- and β-actin cytoskeletal structure and suggest that the regulation of these structures is different.

scholarly journals Modulation of actin isoform expression before the transition from experimental compensated pressure-overload cardiac hypertrophy to decompensation

2009 ◽  
Vol 296 (5) ◽  
pp. H1625-H1632 ◽  
Author(s):  
Roberta Berni ◽  
Monia Savi ◽  
Leonardo Bocchi ◽  
Francesca Delucchi ◽  
Ezio Musso ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Smooth Muscle Actin ◽  
Pressure Overload ◽  
Calcium Transients ◽  
Alpha Smooth Muscle Actin ◽  
Aortic Banding ◽  
Lv Mass ◽  
Actin Isoform ◽  
Contraction And Relaxation ◽  
Kinetics Of

In a rat model of long-lasting pressure-overload hypertrophy, we investigated whether changes in the relative expression of myocardial actin isoforms are among the early signs of ventricular mechanical dysfunction before the transition toward decompensation. Forty-four rats with infrarenal aortic banding (AC rats) were studied. Hemodynamic parameters were measured 1 mo (AC1 group; n = 20) or 2 mo (AC2; n = 24) after aortic ligature. Then subgroups of AC1 and AC2 left ventricles (LV) were used to evaluate 1) LV anatomy and fibrosis (morphometry), 2) expression levels (immunoblotting) and spatial distribution (immunohistochemistry) of alpha-skeletal actin (α-SKA), alpha-cardiac actin (α-CA), and alpha-smooth muscle actin (α-SMA), and 3) cell mechanics and calcium transients in enzimatically isolated myocytes. Although the two AC groups exhibited a comparable degree of hypertrophy (+30% in LV mass; +20% in myocyte surface) and a similar increase in the amount of fibrosis compared with control animals (C group; n = 22), a worsening of LV mechanical performance was observed only in AC2 rats at both organ and cellular levels. Conversely, AC1 rats exhibited enhanced LV contractility and preserved cellular contractile behavior associated with increased calcium transients. Alpha-SKA expression was upregulated (+60%) in AC1. In AC2 ventricles, prolonged hypertension also induced a significant increase in α-SMA expression, mainly at the level of arterial vessels. No significant differences among groups were observed in α-CA expression. Our findings suggest that α-SKA expression regulation and wall remodeling of coronary arterioles participate in the development of impaired kinetics of contraction and relaxation in prolonged hypertension before the occurrence of marked histopathologic changes.

Isolation and characterization of six different chicken actin genes

1984 ◽  
Vol 4 (11) ◽  
pp. 2498-2508
Author(s):  
K S Chang ◽  
W E Zimmer ◽  
D J Bergsma ◽  
J B Dodgson ◽  
R J Schwartz
Keyword(s):  
Dna Sequences ◽  
Genomic Dna ◽  
Genomic Library ◽  
Smooth Muscle Actin ◽  
Actin Gene ◽  
Muscle Actin ◽  
Repeated Dna ◽  
Alpha Smooth Muscle Actin ◽  
Actin Genes ◽  
Actin Isoform

Genes representing six different actin isoforms were isolated from a chicken genomic library. Cloned actin cDNAs as well as tissue-specific mRNAs enriched in different actin species were used as hybridization probes to group individual actin genomic clones by their relative thermal stability. Restriction maps showed that these actin genes were derived from separate and nonoverlapping regions of genomic DNA. Of the six isolated genes, five included sequences from both the 5' and 3' ends of the actin-coding area. Amino acid sequence analysis from both the NH2- and COOH-terminal regions provided for the unequivocal identification of these genes. The striated isoforms were represented by the isolated alpha-skeletal, alpha-cardiac, and alpha-smooth muscle actin genes. The nonmuscle isoforms included the beta-cytoplasmic actin gene and an actin gene fragment which lacked the 5' coding and flanking sequence; presumably, this region of DNA was removed from this gene during construction of the genomic library. Unexpectedly, a third nonmuscle chicken actin gene was found which resembled the amphibian type 5 actin isoform (J. Vandekerckhove, W. W. Franke, and K. Weber, J. Mol. Biol., 152:413-426). This nonmuscle actin type has not been previously detected in warm-blooded vertebrates. We showed that interspersed, repeated DNA sequences closely flanked the alpha-skeletal, alpha-cardiac, beta-, and type 5-like actin genes. The repeated DNA sequences which surround the alpha-skeletal actin-coding regions were not related to repetitious DNA located on the other actin genes. Analysis of genomic DNA blots showed that the chicken actin multigene family was represented by 8 to 10 separate coding loci. The six isolated actin genes corresponded to 7 of 11 genomic EcoRI fragments. Only the alpha-smooth muscle actin gene was shown to be split by an EcoRI site. Thus, in the chicken genome each actin isoform appeared to be encoded by a single gene.

Sphingolipids as mediators of effects of platelet-derived growth factor in vascular smooth muscle cells

1993 ◽  
Vol 265 (3) ◽  
pp. C740-C747 ◽  
Author(s):  
L. S. Jacobs ◽  
M. Kester
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Dna Synthesis ◽  
Vascular Smooth Muscle Cells ◽  
Platelet Derived Growth Factor ◽  
Sphingolipid Metabolism ◽  
A7r5 Cell ◽  
A7r5 Cells

The role of sphingolipids in mediating the action of platelet-derived growth factor (PDGF) has been investigated in the vascular smooth muscle-derived A7r5 cell line. L-Cycloserine (2 mM), an inhibitor of sphingolipid synthesis, caused time-dependent inhibition of [3H]serine incorporation into [3H]sphingomyelin in A7r5 cells. PDGF-AB (10 ng/ml), PDGF-BB (10 ng/ml), or sphingosine (10 microM) independently stimulated [3H]thymidine incorporation into DNA in A7r5 cells. L-Cycloserine (2 mM) inhibited stimulation of DNA synthesis by both PDGF-AB and PDGF-BB. L-Cycloserine (2 mM, 16 h) did not affect the ability of PDGF or sphingosine to increase intracellular free calcium ([Ca2+]i) in A7r5 cells loaded with the fluorescent indicator fura 2. Measurement of adenine nucleotide levels in A7r5 cell extracts by reverse-phase high-performance liquid chromatography indicated that treatment with L-cycloserine did not adversely affect cellular metabolism. To determine directly whether PDGF activates sphingolipid metabolism, A7r5 cells were labeled with [3H]serine for 48 h and then treated with PDGF-AB (10 ng/ml) for 1 h. Sphingolipids were separated by thin-layer chromatography and quantified by liquid scintillation counting. PDGF-AB stimulated an increase in [3H]sphingosine from 25.5 +/- 3.0 to 37.5 +/- 4.1 counts.min-1 (cpm).micrograms protein-1 and a concomitant decrease in [3H]ceramide from 24.3 +/- 3.2 to 18.5 +/- 2.9 cpm/micrograms protein. These data suggest that the PDGF-stimulated increase in [Ca2+]i is not sufficient for induction of DNA synthesis and that mitogenic effects of PDGF in vascular smooth muscle cells are mediated by sphingolipid metabolism.

Sequence analysis of an actin isoform in the flatworm Diphyllobothrium dendriticum (Cestoda)

Hydrobiologia ◽  
1995 ◽  
Vol 305 (1-3) ◽  
pp. 283-283
Author(s):  
Monica H. Wahlberg ◽  
Kaj A. Karlstedt ◽  
Gun I. L. Paatero
Keyword(s):  
Sequence Analysis ◽  
Diphyllobothrium Dendriticum ◽  
Actin Isoform

Cloning and Tissue-Specific Expression of Predicted Pisum sativum Actin Isoform PEAc14-1

2013 ◽  
Vol 51 (9-10) ◽  
pp. 722-727 ◽  
Author(s):  
Shaobin Zhang ◽  
Fangsheng Cheng ◽  
Can Wang ◽  
Lijun Zhang ◽  
Yingfeng An
Keyword(s):  
Pisum Sativum ◽  
Specific Expression ◽  
Tissue Specific ◽  
Tissue Specific Expression ◽  
Actin Isoform

ERK-1/2 And P38 MAPK Signaling In The A7R5 Cell Line Following Fluprostenal Stimulation

2005 ◽  
Vol 37 (Supplement) ◽  
pp. S154
Author(s):  
Kevin M. Rice ◽  
Sreevani Uddemaari ◽  
Devashish Desai ◽  
Randy S. Kinnard ◽  
Robert Harris ◽  
...  
Keyword(s):  
Cell Line ◽  
P38 Mapk ◽  
Mapk Signaling ◽  
A7r5 Cell ◽  
A7r5 Cell Line ◽  
Line Following

scholarly journals The elusive actin cytoskeleton of a green alga expressing both conventional and divergent actins

2019 ◽  
Vol 30 (22) ◽  
pp. 2827-2837 ◽  
Author(s):  
Evan W. Craig ◽  
David M. Mueller ◽  
Brae M. Bigge ◽  
Miroslava Schaffer ◽  
Benjamin D. Engel ◽  
...  
Keyword(s):  
Green Alga ◽  
Actin Filaments ◽  
Electron Tomography ◽  
Filamentous Actin ◽  
Cellular Processes ◽  
Cellular Environment ◽  
Actin Structure ◽  
Actin Isoform ◽  
Labeling Method

The green alga Chlamydomonas reinhardtii is a leading model system to study photosynthesis, cilia, and the generation of biological products. The cytoskeleton plays important roles in all of these cellular processes, but to date, the filamentous actin network within Chlamydomonas has remained elusive. By optimizing labeling conditions, we can now visualize distinct linear actin filaments at the posterior of the nucleus in both live and fixed vegetative cells. Using in situ cryo-electron tomography, we confirmed this localization by directly imaging actin filaments within the native cellular environment. The fluorescently labeled structures are sensitive to the depolymerizing agent latrunculin B (Lat B), demonstrating the specificity of our optimized labeling method. Interestingly, Lat B treatment resulted in the formation of a transient ring-like filamentous actin structure around the nucleus. The assembly of this perinuclear ring is dependent upon a second actin isoform, NAP1, which is strongly up-regulated upon Lat B treatment and is insensitive to Lat B–induced depolymerization. Our study combines orthogonal strategies to provide the first detailed visual characterization of filamentous actins in Chlamydomonas, allowing insights into the coordinated functions of two actin isoforms expressed within the same cell.

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