The calcium-binding activity of fish scale protein  hydrolysates

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.

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

PLoS ONE ◽

10.1371/journal.pone.0056839 ◽

2013 ◽

Vol 8 (2) ◽

pp. e56839 ◽

Cited By ~ 11

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

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Novel Peptide with Specific Calcium-Binding Capacity from Schizochytrium sp. Protein Hydrolysates and Calcium Bioavailability in Caco-2 Cells

Marine Drugs ◽

10.3390/md15010003 ◽

2016 ◽

Vol 15 (1) ◽

pp. 3 ◽

Cited By ~ 19

Author(s):

Xixi Cai ◽

Jiaping Lin ◽

Shaoyun Wang

Keyword(s):

Calcium Binding ◽

Binding Capacity ◽

Protein Hydrolysates ◽

Calcium Bioavailability

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

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y75-158 ◽

1975 ◽

Vol 53 (6) ◽

pp. 1135-1140 ◽

Cited By ~ 27

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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