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

1995 ◽  
Vol 11 (5) ◽  
pp. 28-36 ◽  
Author(s):  
V. M. Danilova ◽  
N. V. Kulikova ◽  
V. S. Tregubov ◽  
V. S. Omelyanuk ◽  
A. M. Filenko
Keyword(s):  
Smooth Muscle ◽  
Regulatory Protein ◽  
Protein Component ◽  
Muscle Filaments

ATP-sensitive K+ channels in pancreatic, cardiac, and vascular smooth muscle cells

1998 ◽  
Vol 274 (1) ◽  
pp. C25-C37 ◽  
Author(s):  
Hisashi Yokoshiki ◽  
Masanori Sunagawa ◽  
Takashi Seki ◽  
Nicholas Sperelakis
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Myocardial Protection ◽  
Regulatory Protein ◽  
Intrinsic Property ◽  
Sulfonylurea Receptor ◽  
Type K ◽  
Channel Opening ◽  
Electrophysiological Studies ◽  
Atp Sensing

ATP-sensitive K+(KATP) channels are therapeutic targets for several diseases, including angina, hypertension, and diabetes. This is because stimulation of KATP channels is thought to produce vasorelaxation and myocardial protection against ischemia, whereas inhibition facilitates insulin secretion. It is well known that native KATP channels are inhibited by ATP and sulfonylurea (SU) compounds and stimulated by nucleotide diphosphates and K+channel-opening drugs (KCOs). Although these characteristics can be shared with KATP channels in different tissues, differences in properties among pancreatic, cardiac, and vascular smooth muscle (VSM) cells do exist in terms of the actions produced by such regulators. Recent molecular biology and electrophysiological studies have provided useful information toward the better understanding of KATPchannels. For example, native KATPchannels appear to be a complex of a regulatory protein containing the SU-binding site [sulfonylurea receptor (SUR)] and an inward-rectifying K+ channel (Kir) serving as a pore-forming subunit. Three isoforms of SUR (SUR1, SUR2A, and SUR2B) have been cloned and found to have two nucleotide-binding folds (NBFs). It seems that these NBFs play an essential role in conferring the MgADP and KCO sensitivity to the channel, whereas the Kir channel subunit itself possesses the ATP-sensing mechanism as an intrinsic property. The molecular structure of KATPchannels is thought to be a heteromultimeric (tetrameric) assembly of these complexes: Kir6.2 with SUR1 (SUR1/Kir6.2, pancreatic type), Kir6.2 with SUR2A (SUR2A/Kir6.2, cardiac type), and Kir6.1 with SUR2B (SUR2B/Kir6.1, VSM type) [i.e., (SUR/Kir6. x)4]. It remains to be determined what are the molecular connections between the SUR and Kir subunits that enable this unique complex to work as a functional KATP channel.

Regulatory Protein of Vascular Smooth Muscle

1976 ◽  
Vol 80 (4) ◽  
pp. 899-901 ◽  
Author(s):  
Nobuo ITO ◽  
Takuji TAKAGI ◽  
Ken HOTTA
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Regulatory Protein

Agonist-induced association of tropomyosin with protein kinase Cα in colonic smooth muscle

2005 ◽  
Vol 288 (2) ◽  
pp. G268-G276 ◽  
Author(s):  
Sita Somara ◽  
Haiyan Pang ◽  
Khalil N. Bitar
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Thin Filament ◽  
Regulatory Protein ◽  
Direct Interaction ◽  
Muscle Cells ◽  
Smooth Muscle Contraction ◽  
Particulate Fraction ◽  
Calcium Dependent

Smooth muscle contraction regulated by myosin light chain phosphorylation is also regulated at the thin-filament level. Tropomyosin, a thin-filament regulatory protein, regulates contraction by modulating actin-myosin interactions. Present investigation shows that acetylcholine induces PKC-mediated and calcium-dependent phosphorylation of tropomyosin in colonic smooth muscle cells. Our data also shows that acetylcholine induces a significant and sustained increase in PKC-mediated association of tropomyosin with PKCα in the particulate fraction of colonic smooth muscle cells. Immunoblotting studies revealed that in colonic smooth muscle cells, there is no significant change in the amount of tropomyosin or actin in particulate fraction in response to acetylcholine, indicating that the increased association of tropomyosin with PKCα in the particulate fraction may be due to acetylcholine-induced translocation of PKCα to the particulate fraction. To investigate whether the association of PKCα with tropomyosin was due to a direct interaction, we performed in vitro direct binding assay. Tropomyosin cDNA amplified from colonic smooth muscle mRNA was expressed as GST-tropomyosin fusion protein. In vitro binding experiments using GST-tropomyosin and recombinant PKCα indicated direct interaction of tropomyosin with PKCα. PKC-mediated phosphorylation of tropomyosin and direct interaction of PKCα with tropomyosin suggest that tropomyosin could be a substrate for PKC. Phosphorylation of tropomyosin may aid in holding the slided tropomyosin away from myosin binding sites on actin, resulting in actomyosin interaction and sustained contraction.

Regulation of sarcoplasmic reticulum Ca2+ reuptake in porcine airway smooth muscle

2008 ◽  
Vol 294 (4) ◽  
pp. L787-L796 ◽  
Author(s):  
Venkatachalem Sathish ◽  
Figen Leblebici ◽  
Sertac N. Kip ◽  
Michael A. Thompson ◽  
Christina M. Pabelick ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Airway Smooth Muscle ◽  
Small Interfering Rna ◽  
Regulatory Protein ◽  
Plasmic Reticulum ◽  
Intracellular Ca ◽  
Subsequent Exposure ◽  
Interfering Rna ◽  
Serca Inhibition

Regulation of intracellular Ca2+ concentration ([Ca2+]i) in airway smooth muscle (ASM) during agonist stimulation involves sarcoplasmic reticulum (SR) Ca2+ release and reuptake. The sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) is key to replenishment of SR Ca2+ stores. We examined regulation of SERCA in porcine ASM: our hypothesis was that the regulatory protein phospholamban (PLN) and the calmodulin (CaM)-CaM kinase (CaMKII) pathway (both of which are known to regulate SERCA in cardiac muscle) play a role. In porcine ASM microsomes, we examined the expression and extent of PLN phosphorylation after pharmacological inhibition of CaM (with W-7) vs. CaMKII (with KN-62/KN-93) and found that PLN is phosphorylated by CaMKII. In parallel experiments using enzymatically dissociated single ASM cells loaded with the Ca2+ indicator fluo 3 and imaged using fluorescence microscopy, we measured the effects of PLN small interfering RNA, W-7, and KN-62 on [Ca2+]i responses to ACh and direct SR stimulation. PLN small interfering RNA slowed the rate of fall of [Ca2+]i transients to 1 μM ACh, as did W-7 and KN-62. The two inhibitors additionally slowed reuptake in the absence of PLN. In other cells, preexposure to W-7 or KN-62 did not prevent initiation of ACh-induced [Ca2+]i oscillations (which were previously shown to result from repetitive SR Ca2+ release/reuptake). However, when ACh-induced [Ca2+]i oscillations reached steady state, subsequent exposure to W7 or KN-62 decreased oscillation frequency and amplitude and slowed the fall time of [Ca2+]i transients, suggesting SERCA inhibition. Exposure to W-7 completely abolished ongoing ACh-induced [Ca2+]i oscillations in some cells. Preexposure to W-7 or KN-62 did not affect caffeine-induced SR Ca2+ release, indicating that ryanodine receptor channels were not directly inhibited. These data indicate that, in porcine ASM, the CaM-CaMKII pathway regulates SR Ca2+ reuptake, potentially through altered PLN phosphorylation.

scholarly journals Primary Mesenchymal Cells Isolated from SPARC-null Mice Exhibit Altered Morphology and Rates of Proliferation

1999 ◽  
Vol 10 (5) ◽  
pp. 1569-1579 ◽  
Author(s):  
Amy D. Bradshaw ◽  
Aleksandar Francki ◽  
Kouros Motamed ◽  
Chin Howe ◽  
E. Helene Sage
Keyword(s):  
Cell Cycle ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Mesangial Cells ◽  
Regulatory Protein ◽  
Focal Adhesions ◽  
Muscle Cells ◽  
Matricellular Protein ◽  
Cell Periphery ◽  
Wild Type

SPARC (secreted protein acidic and rich in cysteine)/BM 40/osteonectin is a matricellular protein shown to function as a counteradhesive factor that induces cell rounding and as an inhibitor of cell proliferation. These activities have been defined in cell culture, in which interpretation has been complicated by the presence of endogenous SPARC. We therefore sought to determine whether cell shape and proliferation would be affected by the absence of SPARC. Mesangial cells, fibroblasts, and aortic smooth muscle cells were isolated from SPARC-null and age-matched, wild-type mice. In contrast to wild-type cells, SPARC-null mesangial cells exhibited a flat morphology and an altered actin cytoskeleton. In addition, vinculin-containing focal adhesions were distributed over the center of SPARC-null cells, whereas in wild-type cells, the number of focal adhesions was reduced, and these structures were restricted largely to the cell periphery. Although the SPARC-null fibroblasts did not display overt differences in cell morphology, the cells responded to exogenous recombinant SPARC by rounding up in a manner similar to that of wild-type fibroblasts. Thus, the expression of endogenous SPARC is not required for the response of cells to SPARC. Additionally, SPARC-null mesangial cells, fibroblasts, and smooth muscle cells proliferated faster than their respective wild-type counterparts. Null cells also showed a greater sensitivity to the inhibition of cell cycle progression by the addition of recombinant SPARC. The increased proliferation rate of SPARC-null cells appeared to be mediated, at least in part, by an increase in the cell cycle regulatory protein cyclin A. We conclude that the expression of SPARC influences the cellular architecture of mesangial cells and that SPARC plays a role in the regulation of cell cycle in mesangial cells, fibroblasts, and smooth muscle cells.

Caldesmon: A common actin-linked regulatory protein in the smooth muscle and nonmuscle contractile system

1988 ◽  
Vol 37 (3) ◽  
pp. 317-325 ◽  
Author(s):  
Kenji Sobue ◽  
Keiko Kanda ◽  
Toshihiko Tanaka ◽  
Noboru Ueki
Keyword(s):  
Smooth Muscle ◽  
Regulatory Protein ◽  
Contractile System
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