scholarly journals Calcium-ion-binding activity in human small-intestinal mucosal cytosol Purification of two proteins and interrelationship of calcium-binding fractions

1981 ◽  
Vol 197 (1) ◽  
pp. 55-65 ◽  
Author(s):  
M Davie
Keyword(s):  
Molecular Weight ◽  
Calcium Binding ◽  
Binding Proteins ◽  
Binding Protein ◽  
Mammalian Species ◽  
Binding Activity ◽  
Calcium Binding Proteins ◽  
Calcium Binding Protein ◽  
Small Intestinal Mucosa ◽  
Small Intestinal

Ca2+-binding activity was investigated in human small-intestinal mucosal cytosol. Binding was detected in fractions with molecular weights of 28000 and about 900000, as determined by gel filtration. No binding was found at molecular weight 12000-13000 (the molecular weight of calcium-binding protein in lower mammalian species) until the cytosol had been subjected to a hollow-fibre-filtration step. The appearance of Ca2+-binding at molecular weight 12000-13000 was associated with a decline in the 28000-mol.wt. calcium-binding fraction. The 12000-13000-mol.wt. fraction contained two distinct calcium-binding proteins. One of these proteins had properties similar to those of pig calcium-binding protein. Antiserum to this protein reacted against the 28000-mol.wt calcium-binding fraction in cytosol from human small-intestinal mucosa and from human kidney. An immunoassay method for one of the calcium-binding proteins was established. In normal duodenal mucosa the concentration was 915 micrograms/g and in the ileum it was 443 micrograms/g of mucosa. A subject with hypercalcaemic sarcoidosis had 1200 micrograms/g of mucosa in the jejunum, and a subject with an undetectable concentration of plasma 25-hydroxycholecalciferol had concentrations of calcium-binding protein in the mucosa similar to those found in normal subjects.

Expression of calcium-binding proteins in pathways from the nucleus of the basal optic root to the cerebellum in pigeons

2008 ◽  
Vol 25 (5-6) ◽  
pp. 701-707 ◽  
Author(s):  
DOUGLAS R.W. WYLIE ◽  
JANELLE M.P. PAKAN ◽  
CRISTIÁN GUTIÉRREZ-IBÁÑEZ ◽  
ANDREW N. IWANIUK
Keyword(s):  
Protein Expression ◽  
Calcium Binding ◽  
Binding Proteins ◽  
Binding Protein ◽  
Calcium Binding Proteins ◽  
Calcium Binding Protein ◽  
Neural Pathways ◽  
Optokinetic Response ◽  
Neuronal Tracing ◽  
Fluorescent Immunohistochemistry

AbstractCalcium-binding protein expression has proven useful in delineating neural pathways. For example, in birds, calbindin is strongly expressed in the tectofugal pathway, whereas parvalbumin (PV) is strongly expressed in the thalamofugal pathway. Whether neurons within other visual regions also differentially express calcium-binding proteins, however, has not been extensively studied. The nucleus of the basal optic root (nBOR) is a retinal-recipient nucleus that is critical for the generation of the optokinetic response. The nBOR projects to the cerebellum both directly and indirectly via the inferior olive (IO). The cerebellar and IO projections originate from different neurons within the nBOR, but whether they can also be differentiated based on calcium-binding protein expression is unknown. In this study, we combined retrograde neuronal tracing from the cerebellum and IO with fluorescent immunohistochemistry for PV and calretinin (CR) in the nBOR of pigeons. We found that about half (52.3%) of the cerebellar-projecting neurons were CR+ve, and about one-third (33.6%) were PV+ve. Most (90%) of these PV+ve cells were also labeled for CR. In contrast, very few of the IO-projecting neurons expressed CR or PV (≤2%). Thus, the direct nBOR–cerebellar and indirect nBOR–olivocerebellar pathways to the cerebellum can be distinguished based on the differential expression of CR and PV.

Calcium Binding Proteins in the Duodenal Mucosa of the Chick, Rat, Pig, and Human

1972 ◽  
Vol 50 (7) ◽  
pp. 758-765 ◽  
Author(s):  
A. J. W. Hitchman ◽  
Joan E. Harrison
Keyword(s):  
Molecular Weight ◽  
Vitamin D ◽  
Calcium Ions ◽  
Calcium Binding ◽  
Binding Protein ◽  
Gel Filtration ◽  
Duodenal Mucosa ◽  
Calcium Binding Proteins ◽  
Calcium Binding Protein ◽  
Electrophoretic Mobilities

A calcium binding protein has been demonstrated in human duodenal mucosa which we believe to be human vitamin D dependent CaBP. Sephadex gel filtration demonstrated that the duodenal mucosa of both the human and pig contained a calcium binding protein with a similar molecular weight to the reported vitamin D dependent rat CaBP (M.W. 12 000–13 000) but dissimilar to chick CaBP (M.W. 24 000–28 000). In addition the rat, pig, and human mucosa contained a high molecular weight calcium binding protein which is probably not vitamin D dependent.A relatively simple procedure, utilizing the tagging of CaBP by 47Ca, has been developed to partially purify normal pig CaBP by Sephadex gel filtration. Further fractionation of the 12 000–13 000 M.W. area, using disc electrophoretic procedures, separated two calcium binding proteins which had similar electrophoretic mobilities and calcium binding formation constants (3.5 and 5.5 × 106, respectively), indicating that both are forms of CaBP but that either one or both have been altered during the procedures. The electrophoretic mobilities of both of these proteins are relatively low in the presence of calcium ions but much greater when calcium ions are removed by chelation with EDTA. This finding should facilitate both the identification and purification of mammalian CaBP.

scholarly journals Nonstructural 5A Protein of Hepatitis C Virus Regulates Soluble Resistance-Related Calcium-Binding Protein Activity for Viral Propagation

2015 ◽  
Vol 90 (6) ◽  
pp. 2794-2805 ◽  
Author(s):  
Giao V. Q. Tran ◽  
Trang T. D. Luong ◽  
Eun-Mee Park ◽  
Jong-Wook Kim ◽  
Jae-Woong Choi ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Protein Interaction ◽  
Calcium Binding ◽  
Crucial Role ◽  
Binding Protein ◽  
Binding Activity ◽  
Calcium Binding Protein ◽  
Virus Propagation ◽  
Ns5a Protein

ABSTRACTHepatitis C virus (HCV) is a major cause of chronic liver disease and is highly dependent on cellular proteins for virus propagation. To identify the cellular factors involved in HCV propagation, we recently performed protein microarray assays using the HCV nonstructural 5A (NS5A) protein as a probe. Of 90 cellular protein candidates, we selected the soluble resistance-related calcium-binding protein (sorcin) for further characterization. Sorcin is a calcium-binding protein and is highly expressed in certain cancer cells. We verified that NS5A interacted with sorcin through domain I of NS5A, and phosphorylation of the threonine residue 155 of sorcin played a crucial role in protein interaction. Small interfering RNA (siRNA)-mediated knockdown of sorcin impaired HCV propagation. Silencing of sorcin expression resulted in a decrease of HCV assembly without affecting HCV RNA and protein levels. We further demonstrated that polo-like kinase 1 (PLK1)-mediated phosphorylation of sorcin was increased by NS5A. We showed that both phosphorylation and calcium-binding activity of sorcin were required for HCV propagation. These data indicate that HCV modulates sorcin activity via NS5A protein for its own propagation.IMPORTANCESorcin is a calcium-binding protein and regulates intracellular calcium homeostasis. HCV NS5A interacts with sorcin, and phosphorylation of sorcin is required for protein interaction. Gene silencing of sorcin impaired HCV propagation at the assembly step of the HCV life cycle. Sorcin is phosphorylated by PLK1 via protein interaction. We showed that sorcin interacted with both NS5A and PLK1, and PLK1-mediated phosphorylation of sorcin was increased by NS5A. Moreover, calcium-binding activity of sorcin played a crucial role in HCV propagation. These data provide evidence that HCV regulates host calcium metabolism for virus propagation, and thus manipulation of sorcin activity may represent a novel therapeutic target for HCV.

scholarly journals The Heparin-Binding Activity of Secreted Modular Calcium-Binding Protein 1 (SMOC-1) Modulates Its Cell Adhesion Properties

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e56839 ◽  
Author(s):  
Marina Klemenčič ◽  
Marko Novinec ◽  
Silke Maier ◽  
Ursula Hartmann ◽  
Brigita Lenarčič
Keyword(s):  
Cell Adhesion ◽  
Calcium Binding ◽  
Binding Protein ◽  
Binding Activity ◽  
Calcium Binding Protein ◽  
Heparin Binding ◽  
Adhesion Properties

Calcium-binding proteins in a vorticellid contractile organelle

1975 ◽  
Vol 19 (1) ◽  
pp. 203-213
Author(s):  
W.B. Amos ◽  
L.M. Routledge ◽  
F.F. Yew
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Calcium Binding ◽  
Binding Proteins ◽  
Sodium Dodecyl ◽  
Aromatic Amino Acids ◽  
Calcium Binding Proteins ◽  
Polyacrylamide Gels ◽  
Protein Species ◽  
Low Concentrations

The proteins of the contractile spasmoneme of Zoothamnium have been examined for comparison with other motile systems. Though capable of calcium-induced contraction, glycerinated preparations of the spasmoneme contain neither actin nor tubulin at levels that can be detected in polyacrylamide gels. Sixty per cent of the protein in sodium dodecyl sulphate gels migrates in a band at a molecular weight of approximately 20,000, consisting largely of 2 similar protein species which are here given the name of spasmins. The amino acid composition of 2 spasmin fractions has been determined by a fluorimetric method. They are rich in Asx, Glx and serine, but have few aromatic amino acids and no cystine or methionine. In calcium-buffered polyacrylamide gels, it was observed that a reduction in the electrophoretic mobility of the spasmins was induced specifically by calcium (but not magnesium) at the same low concentrations as induce contraction. This indicates that the spasmins are calcium-binding proteins which may be involved directly in the calcium-induced contraction of the spasmoneme.

Radioimmunoassay Studies of Intestinal Calcium-binding Protein in the Pig. II. The Distribution of Intestinal CaBP in Pig Tissues

1975 ◽  
Vol 53 (6) ◽  
pp. 1135-1140 ◽  
Author(s):  
B. M. Arnold ◽  
M. Kuttner ◽  
D. M. Willis ◽  
A. J. W. Hitchman ◽  
J. E. Harrison ◽  
...  
Keyword(s):  
Small Intestine ◽  
Calcium Binding ◽  
Binding Protein ◽  
Gel Filtration ◽  
Protein S ◽  
Binding Activity ◽  
Calcium Binding Protein ◽  
Distal Small Intestine ◽  
Specific Radioimmunoassay ◽  
Kidney Liver

Using a specific radioimmunoassay for porcine intestinal calcium-binding protein (CaBP), we have measured the concentration of CaBP in the various tissues and organs of normal pigs. Intestinal CaBP was present in highest concentration in the upper small intestine, with lower concentrations in the distal small intestine. Intestinal CaBP was also found, in lower concentrations, in kidney, liver, thyroid, pancreas, and blood. In all other tissues, including parathyroid, bone, skeletal muscle, and brain, CaBP immunoreactivity was undetectable or less than in blood. The elution profile of calcium-binding activity and immunoreactivity from gel filtration analysis of kidney and parathyroid extracts suggest that the calcium-binding protein in the parathyroid gland, and the major calcium-binding protein(s) in the kidney, are chemically and immunochemically different from intestinal CaBP.

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