Some properties of duck gizzard caldesmon.
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ABSTRACT:
SUBMITTER: Vorotnikov AV
PROVIDER: S-EPMC1149893 | biostudies-other | 1991 Jan
REPOSITORIES: biostudies-other
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Project description:Chicken gizzard smooth muscle contains two major calmodulin-binding proteins: caldesmon (11.1 microM; Mr 141 000) and myosin light-chain kinase (4.6 microM; Mr 136 000), both of which are associated with the contractile apparatus. The amino acid composition of caldesmon is distinct from that of myosin light-chain kinase and is characterized by a very high glutamic acid content (25.5%), high contents of lysine (13.6%) and arginine (10.3%), and a low aromatic amino acid content (2.4%). Caldesmon lacked myosin light-chain kinase and phosphatase activities and did not compete with either myosin light-chain kinase or cyclic nucleotide phosphodiesterase (both calmodulin-dependent enzymes) for available calmodulin, suggesting that calmodulin may have distinct binding sites for caldesmon on the one hand and myosin light-chain kinase and cyclic nucleotide phosphodiesterase on the other. Consistent with the lack of effect of caldesmon on myosin phosphorylation, caldesmon did not affect the assembly or disassembly of myosin filaments in vitro. As previously shown [Ngai & Walsh (1984) J. Biol. Chem. 259, 13656-13659], caldesmon can be reversibly phosphorylated. The phosphorylation and dephosphorylation of caldesmon were further characterized and the Ca2+/calmodulin-dependent caldesmon kinase was purified; kinase activity correlated with a protein of subunit Mr 93 000. Caldesmon was not a substrate of myosin light-chain kinase or phosphorylase kinase, both calmodulin-activated protein kinases.
| S-EPMC1152673 | biostudies-other
Project description:Caldesmon, an actin- and calmodulin-binding protein of smooth muscle, is a protein serine/threonine kinase capable of Ca2+/calmodulin-dependent autophosphorylation [Scott-Woo & Walsh (1988) Biochem. J. 252, 463-472]. Phosphorylation nullifies the inhibitory effect of caldesmon on the actin-activated Mg2+-ATPase activity of smooth-muscle myosin [Ngai & Walsh (1987) Biochem. J. 244, 417-425]. We have characterized the kinase activity of caldesmon of chicken gizzard smooth muscle. Autophosphorylation requires Ca2+/calmodulin, but is unaffected by other second messengers (Ca2+/phospholipid/diacylglycerol, cyclic AMP or cyclic GMP), and is inhibited by the calmodulin antagonists chlorpromazine and compound 48/80, with 50% inhibition at 39.8 microM and 12.0 ng/ml respectively. Half-maximal activation of autophosphorylation occurs at 60-80 nM-Ca2+ and 0.14 microM-calmodulin, and maximal activity at 0.14-0.18 microM-Ca2+ and 1 microM-calmodulin; activation is gradually lost at higher Ca2+ and calmodulin concentrations. Autophosphorylation is pH-dependent, with maximal activity over the range pH 7-9, and requires free Mg2+ in addition to the MgATP2- substrate. The Km for ATP is 15.6 +/- 4.1 microM (mean +/- S.D., n = 4), and kinase activity is inhibited by increasing ionic strength [half-maximal inhibition at I = 0.094 +/- 0.009 M (mean +/- S.D., n = 4)]. Autophosphorylation does not affect the rate of hydrolysis of caldesmon (free or bound to calmodulin) by alpha-chymotrypsin. However, a slight difference in peptides generated from phospho- and dephospho-forms of caldesmon is observed. The binding of phospho- or dephospho-caldesmon to F-actin protects the protein against chymotryptic digestion, but does not alter the pattern of peptide generation. Characterization of proteolytic fragments of caldesmon generated by alpha-chymotrypsin and Staphylococcus aureus V8 protease enables localization of the phosphorylation sites and the kinase active site within the caldesmon molecule.
| S-EPMC1135315 | biostudies-other
Project description:UnlabelledThe potential role and function of gastrokine-1 (GNK1) in smooth muscle cells is investigated in this work by first establishing a preparative protocol to obtain this native protein from freshly dissected chicken gizzard. Some unexpected biochemical properties of gastrokine-1 were deduced by producing specific polyclonal antibody against the purified protein. We focused on the F-actin interaction with gastrokine-1 and the potential role and function in smooth muscle contractile properties.BackgroundGNK1 is thought to provide mucosal protection in the superficial gastric epithelium. However, the actual role of gastrokine-1 with regards to its known decreased expression in gastric cancer is still unknown. Recently, trefoil factors (TFF) were reported to have important roles in gastric epithelial regeneration and cell turnover, and could be involved in GNK1 interactions. The aim of this study was to evaluate the role and function of GNK1 in smooth muscle cells.Methodology/principal findingsFrom fresh chicken gizzard smooth muscle, an original purification procedure was used to purify a heat soluble 20 kDa protein that was sequenced and found to correspond to the gastrokine-1 protein sequence containing one BRICHOS domain and at least two or possibly three transmembrane regions. The purified protein was used to produce polyclonal antibody and highlighted the smooth muscle cell distribution and F-actin association of GNK1 through a few different methods.Conclusion/significanceAltogether our data illustrate a broader distribution of gastrokine-1 in smooth muscle than only in the gastrointestinal epithelium, and the specific interaction with F-actin highlights and suggests a new role and function of GNK1 within smooth muscle cells. A potential role via TFF interaction in cell-cell adhesion and assembly of actin stress fibres is discussed.
| S-EPMC2588339 | biostudies-literature
Project description:Prey size selection in some bird species is determined by the size of the beak. However, we assumed for bird species swallowing whole prey that a cognitive process may be involved. As cognitive feature, brain mass was used. We hypothesized that the mass of the brain was more strongly positively correlated with prey size than morphological features such as beak volume, gizzard mass and body mass. We tested this hypothesis on eiders Somateria mollissima that swallow the prey whole, by using mean and maximum size of nine prey categories. Eiders were collected at the main wintering grounds in Denmark. As index of brain mass we used head volume, which is positively correlated with brain mass (r2 = 0.73). Head volume of eiders was significantly, positive correlated with mean and maximum size of blue mussels Mytilus edulis, razor clams Ensis directus and all prey sizes combined and the maximum size of draft whelk Hinia reticulata and conch Buccinum undatum. Gizzard mass was also significantly positively correlated with maximum size of draft whelk and conch. Beak volume and body mass was not significantly correlated with the size of any of the nine food items. Analyses of effect size for organs showed that head volume was positively related to prey size, whereas beak volume, gizzard mass and body mass did not show a significant positive relationship. These results indicate that cognitive processes connected to brain mass may be involved in prey size selection by eiders.
| S-EPMC8009388 | biostudies-literature
Project description:In order to illuminate the forming process of salted egg, the effects of the brine solution with different salt concentrations on the physicochemical properties, textural properties, and microstructures of duck eggs were evaluated using conventional physicochemical property determination methods. The results showed that the moisture contents of both the raw and cooked egg whites and egg yolks, the springiness of the raw egg yolks and cooked egg whites exhibited a decreasing trend with the increase in the salting time and salt concentration. The salt content, oil exudation and the hardness of the raw egg yolks showed a constantly increasing trend. Viscosity of the raw egg whites showed an overall trend in which it first deceased and then increased and decreased again, which was similar to the trend of the hardness of the cooked egg whites and egg yolks. As the salting proceeded, the pH value of the raw and cooked egg whites declined remarkably and then declined slowly, whereas the pH of the raw and cooked egg yolks did not show any noticeable changes. The effect of salting on the pH value varied significantly with the salt concentration in the brine solution. Scanning electron microscopy (SEM) revealed that salted yolks consist of spherical granules and embedded flattened porosities. It was concluded that the treatment of salt induces solidification of yolk, accompanied with higher oil exudation and the development of a gritty texture. Different salt concentrations show certain differences.
| S-EPMC5552285 | biostudies-literature
Project description:Caldesmon, an actin-binding protein, can inhibit myosin binding to actin and regulate smooth muscle contraction and relaxation. However, caldesmon has recently attracted attention due to its importance in cancer. The upregulation of caldesmon in several solid cancer tissues has been reported. Caldesmon, as well as its two isoforms, is considered as a biomarker for cancer and a potent suppressor of cancer cell invasion by regulating podosome/invadopodium formation. Therefore, caldesmon may be a promising therapeutic target for diseases such as cancer. Here, we review new studies on the gene transcription, isoform structure, expression, and phosphorylation regulation of caldesmon and discuss its clinical implications in cancer.
| S-EPMC7930484 | biostudies-literature
Project description:The demand for duck meat and eggs in Asian countries increases every year. Duck egg albumen has become an important ingredient in the food industry alongside its hen counterpart, because of its excellent nutritive and functional properties. The major proteins in duck albumen are ovalbumin, ovomucoid, ovomucin, conalbumin, and lysozyme. Comparing with hen albumen, lower contents of ovalbumin, conalbumin, lysozyme and ovoflavoprotein are found in duck albumen. Nevertheless, duck albumen shows better gelling and foaming properties than hen albumen. During storage, duck albumen gel properties are enhanced, while foam volume and foam stability are decreased. Moreover, the changes in quality indices of duck egg including the thinning of the albumen, an increase in albumen pH, loss of water and carbon dioxide occur as storage time is increased. Some processes such as alkaline treatment also cause the loss in nutritive value of egg albumen. In this review, the composition and functional properties of duck albumen and how they are affected by processing conditions are also addressed, in comparison with hen albumen. A better understanding of duck egg albumen would be beneficial so that the food processing industry can exploit the potential of this avian protein.
| S-EPMC6423336 | biostudies-literature
Project description:Gut bacterial communities have been shown to be influenced by diet, host phylogeny and anatomy, but most of these studies have been done in captive animals. Here we compare the bacterial communities in the digestive tract of wild birds. We characterized the gizzard and intestinal microbiota among 8 wild Neotropical bird species, granivorous or frugivorous species of the orders Columbiformes and Passeriformes. We sequenced the V4 region of the 16S rRNA gene in 94 collected samples from 32 wild birds from 5 localities, and compared bacterial communities by foraging guild, organ, locality and bird taxonomy. 16S rRNA gene-based sequencing data were examined using QIIME with linear discriminant analysis effect size (LEfSe) and metabolic pathways were predicted using PICRUSt algorism. We identified 8 bacterial phyla, dominated by Firmicutes, Actinobacteria and Proteobacteria. Beta diversity analyses indicated significant separation of gut communities by bird orders (Columbiformes vs. Passerifomes) and between bird species (p<0.01). In lower intestine, PICRUSt shows a predominance of carbohydrate metabolism in granivorous birds and xenobiotics biodegradation pathways in frugivorous birds. Gizzard microbiota was significantly richer in granivorous, in relation to frugivorous birds (Chao 1; non-parametric t-test, p<0.05), suggesting a microbial gizzard function, beyond grinding food. The results suggest that the most important factor separating the bacterial community structure was bird taxonomy, followed by foraging guild. However, variation between localities is also likely to be important, but this could not been assessed with our study design.
| S-EPMC5868825 | biostudies-literature
Project description:The gizzard is the only gastrointestinal organ for mechanical processing in birds. Many birds use grit in the gizzard to enhance mechanical processing efficiency. We conducted an experiment to test the factors that affect chicken grit use in 68 male layer chicks of Gallus gallus domesticus, which were divided into two different groups in gizzard muscularity (high and low). Within each muscularity group, two different diets were provided (herbivory and non-herbivory) to test whether diet and gizzard muscularity affect grit characteristics including amount, size, and shape (circularity, roundness, and solidity) at different stages of digestion (ingested grit, grit in gizzard, and excreted grit). All animals ingested more grit than they excreted, possibly because excreted grit was below the detection size limit of 0.5 mm of the present study. The amounts of grit ingested and remained in the gizzard were larger in herbivorous groups, but these groups excreted less grit. Larger, rougher grit was selectively ingested by all chicks, but size preferences were especially pronounced in the herbivorous groups. Grit in the gizzard tended to be larger in herbivorous groups, but the grit in excreta was smaller, whereas the size of excreted grit was larger in groups with less muscular gizzards. Grit in the gizzard was much smoother than the offered and ingested grit, especially in the herbivorous, muscular gizzard groups. Excreted grit in all groups was smoother than the offered grit. These results show that diet affects the characteristics of ingested grit, grit in the gizzard, and excreted grit, whereas gizzard muscularity affects the characteristics of grit in the gizzard and excreted grit. The use of larger sizes and amounts of grit by herbivorous groups may be a response to the needs of digesting hard, coarse materials. The recovered behavioral flexibility of grit use might reflect the omnivorous nature of Gallus gallus domesticus and may aid smooth dietary shifts. The results also show that the shape of grit remaining in the gizzard does not reflect the initial shape of ingested grit, in contrast to previously published ideas. Instead, the shape of grit in the gizzard more closely reflects the diet and gizzard muscularity of chicks.
| S-EPMC7666813 | biostudies-literature
Project description:Non-muscle caldesmon (l-CaD) is involved in the regulation of actin cytoskeletal remodeling in the podosome formation, but its function in osteoclastogenesis remains to be determined. In this study, RANKL-induced differentiation of RAW264.7 murine macrophages to osteoclast-like cells (OCs) was used as a model to determine the physiological role of l-CaD and its phosphorylation in osteoclastogenesis. Upon RANKL treatment, RAW264.7 cells undergo cell-cell fusion into multinucleate, and TRAP-positive large OCs with a concomitant increase of l-CaD expression. Using gain- and loss-of-function in OC precursor cells followed by RANKL induction, we showed that the expression of l-CaD in response to RANKL activation is an important event for osteoclastogenesis, and bone resorption. To determine the effect of l-CaD phosphorylation in osteoclastogenesis, three decoy peptides of l-CaD were used with, respectively, Ser-to-Ala mutations at the Erk- and Pak1-mediated phosphorylation sites, and Ser-to-Asp mutation at the Erk-mediated phosphorylation sites. Both the former two peptides competed with the C-terminal segment of l-CaD for F-actin binding and accelerated formation of podosome-like structures in RANKL-induced OCs, while the third peptide did not significantly affect the F-actin binding of l-CaD, and decreased the formation of podosome-like structures in OCs. With the experiments using dephosphorylated and phosphorylated l-CaD mutants, we further showed that dephosphorylated l-CaD mutant facilitated RANKL-induced TRAP activity with an increased cell fusion index, whereas phosphorylated l-CaD decreased the TRAP activity and cell fusion. Our findings suggested that both the level of l-CaD expression and the extent of l-CaD phosphorylation play a role in RANKL-induced osteoclast differentiation.
| S-EPMC5993584 | biostudies-literature