scholarly journals Ca2+-calmodulin binding to caldesmon and the caldesmon-actin-tropomyosin complex. Its role in Ca2+ regulation of the activity of synthetic smooth-muscle thin filaments

1989 ◽  
Vol 257 (3) ◽  
pp. 839-843 ◽  
Author(s):  
K Pritchard ◽  
S B Marston
Keyword(s):  
Smooth Muscle ◽  
Thin Filament ◽  
Smooth Muscle Actin ◽  
Muscle Actin ◽  
Polarization Method ◽  
Thin Filaments ◽  
Calmodulin Binding ◽  
Muscle Thin Filament ◽  
Mgatpase Activity

We measured the concentration of calmodulin required to reverse inhibition by caldesmon of actin-activated myosin MgATPase activity, in a model smooth-muscle thin-filament system, reconstituted in vitro from purified vascular smooth-muscle actin, tropomyosin and caldesmon. At 37 degrees C in buffer containing 120 mM-KCl, 4 microM-Ca2+-calmodulin produced a half-maximal reversal of caldesmon inhibition, but more than 300 microM-Ca2+-calmodulin was necessary at 25 degrees C in buffer containing 60 mM-KCl. The binding affinity (K) of caldesmon for Ca2+-calmodulin was measured by a fluorescence-polarization method: K = 2.7 x 10(6) M-1 at 25 degrees C (60 mM-KCl); K = 1.4 x 10(6) M-1 at 37 degrees C in 70 mM-KCl-containing buffer; K = 0.35 x 10(6) M-1 at 37 degrees C in 120 mM-KCl- containing buffer (pH 7.0). At 37 degrees C/120 mM-KCl, but not at 25 degrees C/60 mM-KCl, Ca2+-calmodulin bound to caldesmon bound to actin-tropomyosin (K = 2.9 x 10(6) M-1). Ca2+ regulation in this system does not depend on a simple competition between Ca2+-calmodulin and actin for binding to caldesmon. Under conditions (37 degrees C/120 mM-KCl) where physiologically realistic concentrations of calmodulin can Ca2+-regulate synthetic thin filaments, Ca2+-calmodulin reverses caldesmon inhibition of actomyosin ATPase by forming a non-inhibited complex of Ca2+-calmodulin-caldesmon-(actin-tropomyosin).

scholarly journals Ca2+-dependent regulation of vascular smooth-muscle caldesmon by S.100 and related smooth-muscle proteins

1991 ◽  
Vol 277 (3) ◽  
pp. 819-824 ◽  
Author(s):  
K Pritchard ◽  
S B Marston
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Bovine Brain ◽  
Protein Yield ◽  
Muscle Actin ◽  
Muscle Proteins ◽  
Related Protein ◽  
Thin Filaments ◽  
S 100 ◽  
Related Proteins

1. We have investigated the ability of bovine brain S.100, and of three related proteins from sheep aorta smooth muscle, to confer Ca(2+)-sensitivity on thin filaments reconstituted from smooth-muscle actin, tropomyosin and caldesmon. 2. At 37 degrees C in pH 7.0 buffer containing 120 mM-KCl, approximately stoichiometric amounts of S.100 reversed caldesmon's inhibition of the activation of myosin MgATPase by smooth-muscle actin-tropomyosin. The [S.100] which reversed by 50% the inhibition by caldesmon (the E.C.50) was 2.5 microM when [caldesmon] = 2-3 microM in the assay mixture. When [KCl] was decreased to 70 mM, E.C.50 = 11.5 microM; at 25 degrees C in 70 mM-KCl, up to 20 microM-S.100 had no effect. When skeletal-muscle actin rather than smooth-muscle actin was used to reconstitute thin filaments, 20 microM-S.100 did reverse inhibition by caldesmon, at 25 degrees C in buffer containing 70 mM-KCl. This dependence on conditions is also characteristic of the calmodulin-caldesmon interaction. 3. These results suggested that S.100 or a related protein might interact with caldesmon in smooth muscle. We therefore attempted to prepare such a protein from sheep aorta. Three proteins were purified: an Mr-17,000 protein (yield 16 mg/kg), an abundant Mr-11,000 protein (yield 48 mg/kg), and an Mr-9000 protein (yield 4 mg/kg). Neither of the last two low-Mr proteins had any effect on activation of myosin MgATPase by reconstituted thin filaments. The protein of Mr 17,000 had Ca(2+)-sensitizing activity, and behaved exactly like brain calmodulin in the assay system.

Alpha-smooth muscle actin expression by fibroblasts is not a marker of hypertrophic scars in vitro

1998 ◽  
Vol 16 ◽  
pp. S129
Author(s):  
Gianni Gerlini ◽  
Francesca Prignano ◽  
Nicola Pimpinelli ◽  
Lorenzo Borgognoni ◽  
Umberto Maria Reali ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Muscle Actin ◽  
Hypertrophic Scars ◽  
Alpha Smooth Muscle Actin ◽  
Actin Expression

scholarly journals Combination of 13-Cis Retinoic Acid and Lovastatin: Marked Antitumor Potential In Vivo in a Pheochromocytoma Allograft Model in Female Athymic Nude Mice

Endocrinology ◽  
2014 ◽  
Vol 155 (7) ◽  
pp. 2377-2390 ◽  
Author(s):  
Svenja Nölting ◽  
Alessio Giubellino ◽  
Yasin Tayem ◽  
Karen Young ◽  
Michael Lauseker ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Retinoic Acid ◽  
Smooth Muscle Actin ◽  
Treated Group ◽  
Muscle Actin ◽  
Tumor Mass ◽  
Viable Tumor ◽  
Over Time

Currently, there are no reliably effective therapeutic options for metastatic pheochromocytoma (PCC) and paraganglioma. Moreover, there are no therapies that may prevent the onset or progression of tumors in patients with succinate dehydrogenase type B mutations, which are associated with very aggressive tumors. Therefore, we tested the approved and well-tolerated drugs lovastatin and 13-cis-retinoic acid (13cRA) in vitro in an aggressive PCC mouse cell line, mouse tumor tissue-derived (MTT) cells, and in vivo in a PCC allograft nude mouse model, in therapeutically relevant doses. Treatment was started 24 hours before sc tumor cell injection and continued for 30 more days. Tumor sizes were measured from outside by caliper and sizes of viable tumor mass by bioluminescence imaging. Lovastatin showed antiproliferative effects in vitro and led to significantly smaller tumor sizes in vivo compared with vehicle treatment. 13cRA promoted tumor cell growth in vitro and led to significantly larger viable tumor mass and significantly faster increase of viable tumor mass in vivo over time compared with vehicle, lovastatin, and combination treatment. However, when combined with lovastatin, 13cRA enhanced the antiproliferative effect of lovastatin in vivo. The combination-treated mice showed slowest tumor growth of all groups with significantly slower tumor growth compared with the vehicle-treated mice and significantly smaller tumor sizes. Moreover, the combination-treated group displayed the smallest size of viable tumor mass and the slowest increase in viable tumor mass over time of all groups, with a significant difference compared with the vehicle- and 13cRA-treated group. The combination-treated tumors showed highest extent of necrosis, lowest median microvessel density and highest expression of α-smooth muscle actin. The combination of high microvessel density and low α-smooth muscle actin is a predictor of poor prognosis in other tumor entities. Therefore, this drug combination may be a well-tolerated novel therapeutic or preventive option for malignant PCC.

? Isoform of smooth muscle actin is expressed in astrocytes in vitro and in vivo

1991 ◽  
Vol 28 (4) ◽  
pp. 601-606 ◽  
Author(s):  
E. Lecain ◽  
F. Alliot ◽  
M. C. Laine ◽  
B. Calas ◽  
B. Pessac
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Muscle Actin

scholarly journals Caldesmon is a Ca2+-regulatory component of native smooth-muscle thin filaments

1985 ◽  
Vol 231 (3) ◽  
pp. 517-522 ◽  
Author(s):  
S B Marston ◽  
W Lehman
Keyword(s):  
Smooth Muscle ◽  
Thin Filament ◽  
Myosin Light Chain ◽  
Potent Inhibitor ◽  
Peptide Mapping ◽  
Smooth Muscles ◽  
Physiological Mechanism ◽  
Thin Filaments ◽  
Muscle Types ◽  
Mgatpase Activity

Thin-filament preparations from four smooth muscle types (gizzard, stomach, trachea, aorta) all activate myosin MgATPase activity, are regulated by Ca2+, and contain actin, tropomyosin and a 120000-140000-Mr protein in the molar proportions 1:1/7:1/26. The 120000-140000-Mr protein from all sources is a potent inhibitor of actomyosin ATPase activity. Peptide-mapping and immunological evidence is presented showing that it is identical with caldesmon. Quantitative immunological data suggest that caldesmon is a component of all the thin filaments and that the thin-filament-bound caldesmon accounts for all the caldesmon in intact tissue. The myosin light-chain kinase content of thin-filament preparations was found to be negligible. We propose that caldesmon-based thin-filament Ca2+ regulation is a physiological mechanism in all smooth muscles.

TGFβ-1 and epithelial-mesenchymal interactions promote smooth muscle gene expression in bone marrow stromal cells: Possible application in therapies for urological defects

2008 ◽  
Vol 31 (11) ◽  
pp. 951-959 ◽  
Author(s):  
C. Becker ◽  
T. Laeufer ◽  
J. Arikkat ◽  
G. Jakse
Keyword(s):  
Bone Marrow ◽  
Smooth Muscle ◽  
Growth Factor ◽  
Stromal Cells ◽  
Bone Marrow Stromal Cells ◽  
Smooth Muscle Actin ◽  
Muscle Actin ◽  
Muscle Gene Expression ◽  
Muscle Gene

Purpose For regenerative and cellular therapies of the urinary tract system, autologous bladder smooth muscle cells (SMCs) have several limitations, including constricted in vitro proliferation capacity and, more importantly, inability to be used in malignant conditions. The use of in vitro (pre-)differentiated multipotential adult progenitor cells may help to overcome the shortcomings associated with primary cells. Methods By mimicking environmental conditions of the bladder wall, we investigated in vitro effects of growth factor applications and epithelial-mesenchymal interactions on smooth muscle gene expression and on the morphological appearance of adherent bone marrow stromal cells (BMSCs). Results Transcription growth factor beta-1 (TGFβ-1) upregulated the transcription of myogenic gene desmin and smooth muscle actin-γ2 in cultured BMSCs. Stimulatory effects were significantly increased by coculture with urothelial cells. Prolonged stimulation times and epigenetic modifications further enhanced transcription levels, indicating a dose-response relationship. Immunocytochemical staining of in vitro-differentiated BMSCs revealed expression of myogenic protein α-smooth muscle actin and desmin, and changes in morphological appearance from a fusiform convex shape to a laminar flattened shape with filamentous inclusions similar to the appearance of bladder SMCs. In contrast to the TGFβ-1 action, application of vascular endothelial growth factor (VEGF) did not affect the cells. Conclusions The combined application of TGFβ-1 and epithelial-mesenchymal interactions promoted in vitro outgrowth of cells with a smooth muscle-like phenotype from a selected adherent murine bone marrow-derived cell population.

scholarly journals Expression of alpha-smooth muscle actin in murine bone marrow stromal cells

Blood ◽  
1991 ◽  
Vol 78 (2) ◽  
pp. 304-309 ◽  
Author(s):  
A Peled ◽  
D Zipori ◽  
O Abramsky ◽  
H Ovadia ◽  
E Shezen
Keyword(s):  
Bone Marrow ◽  
Smooth Muscle ◽  
Cell Lines ◽  
Smooth Muscle Actin ◽  
Muscle Actin ◽  
Alpha Smooth Muscle Actin ◽  
Murine Bone Marrow ◽  
Cellular Origin ◽  
Hematopoietic Activity

Human fibrotic bone marrow (BM) stroma has been shown to contain alpha- smooth muscle actin (alpha-SMA)-positive cells. These closely resemble myofibroblasts that were described in other fibrotic tissues. We studied the expression of alpha-SMA in a series of murine BM-derived stromal cell lines to investigate the cellular origin and functional significance of myofibroblast-like cells in hematopoietic tissues. Although these cell lines differed in their biologic properties, most of them expressed alpha-SMA under certain conditions. Cells expressing alpha-SMA constituted a minor population in post-confluent, growth- arrested cultures. However, the incidence of cells expressing alpha-SMA increased significantly when cultures were transferred to nonconfluent conditions. A similar increase in alpha-SMA-positive cells occurred after a strip of cells was scraped away from the confluent cell layer; the cells of the affected area acquired alpha-SMA-positive contractile phenotype. The relationship between alpha-SMA expression and hematopoietic activity was studied using a cloned cell line of BM origin (14F1.1). The ability of these endothelial-adipocyte cells to support hematopoiesis in vitro was maximal under confluent conditions, whereas their expression of alpha-SMA under such conditions was residual. Moreover, in long-term BM cultures supported by confluent 14F1.1 cells, stromal areas associated with proliferating hematopoietic precursors, known as “cobblestone areas,” were devoid of alpha-SMA- positive cells. These observations suggest that the expression of alpha- SMA is reversible and inversely related to hematopoietic activity.

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