Ca2+ Binding Protein (ca2+ + binding_protein)

Distribution by Scientific Domains
Life Sciences75%

Selected Abstracts

Junctin and the histidine-rich Ca2+ binding protein: potential roles in heart failure and arrhythmogenesis

THE JOURNAL OF PHYSIOLOGY, Issue 13 2009
Tracy J. Pritchard
Contractile dysfunction and ventricular arrhythmias associated with heart failure have been attributed to aberrant sarcoplasmic reticulum (SR) Ca2+ cycling. The study of junctin (JCN) and histidine-rich Ca2+ binding protein (HRC) becomes of particular importance since these proteins have been shown to be critical regulators of Ca2+ cycling. Specifically, JCN is a SR membrane protein, which is part of the SR Ca2+ release quaternary structure that also includes the ryanodine receptor, triadin and calsequestrin. Functionally, JCN serves as a bridge between calsequestrin and the Ca2+ release channel, ryanodine receptor. HRC is a SR luminal Ca2+ binding protein known to associate with both triadin and the sarcoplasmic reticulum Ca2+ -ATPase, and may thus mediate the crosstalk between SR Ca2+ uptake and release. Indeed, evidence from genetic models of JCN and HRC indicate that they are important in cardiophysiology as alterations in these proteins affect SR Ca2+ handling and cardiac function. In addition, downregulation of JCN and HRC may contribute to Ca2+ cycling perturbations manifest in the failing heart, where their protein levels are significantly reduced. This review examines the roles of JCN and HRC in SR Ca2+ cycling and their potential significance in heart failure. [source]

Secretagogin is a new neuroendocrine marker in the human prostate

THE PROSTATE, Issue 5 2007
Katja Adolf
Abstract Background Neuroendocrine (NE) differentiation in prostate cancer (PCa), promoted by NE cell secreted products, appears to be associated with tumor progression, poor prognosis, and hormone-refractory disease. We recently reported secretagogin, a hexa-EF-hand Ca2+ binding protein, as a novel NE marker in carcinoid tumors of the lung and the gastrointestinal tract. The present study analyzes the expression of secretagogin in normal and malign prostate tissue. Methods We analyzed immunoreactivity for secretagogin, chromogranin A (CgA), neuron specific enolase (NSE), and synaptophysin (SYN) in consecutive sections from 87 formalin-fixed paraffin-embedded (FFPE) benign hyperplastic (n,=,10) and prostate adenocarcinoma (n,=,77) specimens. The intracellular distribution of secretagogin, CgA, and NSE was examined by confocal fluorescent microscopy, and we characterized secretagogin in eight samples by Western blotting. Results Secretagogin is cytoplasmic and nuclear expressed in NE and NE differentiated cells, and to a lesser extent in epithelial cells, in the benign prostate and prostate adenocarcinoma cells. Secretagogin stained 82% (46/56) of benign and 71% (48/68) of prostate adenocarcinomas and co-localized with the NE markers CgA and NSE. The expression of secretagogin is significantly correlated to CgA (P,<,0.001) and NSE (P,<,0.048) in prostate adenocarcinoma and to CgA in normal epithelium (P,<,0.028). Conclusions Secretagogin is a novel NE marker in the prostate with more extended immunoreactivity compared to the NE markers CgA, SYN, and NSE. Secretagogin is widely expressed in prostatic adenocarcinoma as opposed to adenocarcinomas in other organs. Prostate 67: 472,484, 2007. © 2007 Wiley-Liss, Inc. [source]

Proteomic analysis of the response of the human neutrophil-like cell line NB-4 after exposure to anthrax lethal toxin

PROTEOMICS - CLINICAL APPLICATIONS, Issue 10 2007
Jun X. Wheeler
Abstract We used 2-D DIGE to analyze the early response of NB-4 cells, a human promyelotic leukemia cell line, exposed to lethal toxin from Bacillus anthracis at the proteome level. After a 2,h exposure, cells were still viable and 43% of spots (n,=,1042) showed a significant change in protein level. We identified 59 spots whose expression had changed significantly, and these reflected cytoskeleton damage, mitochondrial lysis and endoplasmic reticulum stress. Actin filament assembly was disrupted as evidenced by an increase in both actin subunits and phosphorylated cofilin, whilst levels of tropomyosin, tropomodulin and actin related protein 2/3 complex subunit decreased. Lower levels of ATP synthase subunits and mitochondrial inner membrane protein were identified as markers of mitochondrial lysis. Levels of various stress response proteins rose and, uniquely, levels of Ca2+ binding proteins such as translationally controlled tumor protein rose and hippocalcin-like protein 1 decreased. This response may have mitigated effects brought about by mitochondrial lysis and endoplasmic reticulum stress, and delayed or prevented apoptosis in NB-4 cells. These results resemble findings of similar proteomics studies in murine macrophages, although quantitative differences were observed. [source]