scholarly journals Expression of the calcium-binding proteins MRP8 and MRP14 in monocytes is regulated by a calcium-induced suppressor mechanism

1994 ◽  
Vol 301 (3) ◽  
pp. 655-660 ◽  
Author(s):  
J Roth ◽  
M Goebeler ◽  
V Wrocklage ◽  
C van den Bos ◽  
C Sorg
Keyword(s):  
Blot Analysis ◽  
Calcium Binding ◽  
Binding Proteins ◽  
Calcium Ionophore ◽  
Calcium Binding Proteins ◽  
Biologically Active ◽  
Inflammatory Factors ◽  
Transcriptional Level ◽  
Down Regulation ◽  
Biochemical Modification

MRP8 and MRP14 are two calcium-binding proteins of the S-100 family the expression of which is restricted to distinct stages of monocytic differentiation. Heteromeric MRP8/MRP14 complexes have been shown to represent their biologically active forms. However, it is not as yet clear whether biochemical modification of complexes, or regulation on the transcriptional level, are responsible for the control of MRP8/MRP14 expression. Employing Western-blot analysis and metabolic labelling we have demonstrated that patterns and metabolism of MRP8/MRP14 complexes do not change during up- or down-regulation of MRP8/MRP14. By Northern-blot analysis it was shown that MRP8/MRP14 are regulated at the transcriptional level rather than by biochemical modification of the complexes. Elevation of intracellular calcium levels by A23187, as well as by thapsigargin, was found to lead to specific down-regulation of MRP8/MRP14 mRNA which is in contrast with data reported for inflammatory factors such as interleukin-1 or tumour necrosis factor alpha. Concomitant application of actinomycin D and calcium ionophore indicated that this suppressive effect is mediated by decreased synthesis rather than increased degradation of MRP8/MRP14 mRNA. Finally, we demonstrated that calcium-mediated down-regulation of MRP8-MRP14 can be antagonized by cycloheximide, suggesting that a calcium-induced repressor protein is responsible for suppression of MRP8-MRP14 at the transcriptional level. Our data indicate that the function of MRP8-MRP14 is restricted to events associated with early stages of myelomonocytic activation.

Vitamin D independence of small calcium-binding proteins in nonclassical target tissues

1991 ◽  
Vol 260 (5) ◽  
pp. E794-E800
Author(s):  
M. R. Walters ◽  
M. E. Bruns ◽  
R. M. Carter ◽  
P. C. Riggle
Keyword(s):  
Vitamin D ◽  
Rat Brain ◽  
Blot Analysis ◽  
Calcium Binding ◽  
Binding Proteins ◽  
Immunoblot Analysis ◽  
Calcium Binding Proteins ◽  
Northern Analysis ◽  
Dihydroxyvitamin D3 ◽  
Low Levels

The presence and regulation of Ca-binding proteins (CaBPs) were investigated in newly identified 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] target tissues. 45Ca(2+)-blot analysis of proteins in normal rats yielded a 45Ca2+ band comigrating with authentic calmodulin. Additionally, a parvalbumin-like band (mol mass = 15.4 +/- 0.3 kDa) was prominent in prostate, and a strong unidentified 45Ca2+ band was always evident in the testis (mol mass = 23.5 +/- 0.7 kDa). Lung, bladder, and especially prostate demonstrated 45Ca2+ bands comigrating with the intestinal vitamin D-related CaBP (CaBP-D9K; mol mass = 10.9 +/- 0.5 kDa). Most tissues (including testis, heart, and lung) exhibited low levels of a 45Ca2+ band comigrating with the renal CaBP-D28K (mol mass = 28.3 +/- 0.4 kDa). Importantly, 45Ca2+ binding to all detectable CaBPs was unchanged in these four tissues in vitamin D-deficient rats, despite substantial downregulation of the intestinal CaBP-D9K and renal CaBP-D28K. Neither immunoblot analysis (rabbit anti-rat renal CaBP-D28K) nor Northern analysis (rat brain CaBP-D28K cDNA) provided evidence for coidentity of the 28-kDa 45Ca2+ band with the CaBP-D28K. Conversely, immunoblot analysis of lung, but not prostate, cytosol provided evidence for specific immunocross-reactivity to rabbit anti-rat intestinal CaBP-D9K. Immunoblot analysis of the 9-kDa CaBP in lung further confirmed its vitamin D independence. In conclusion, the vitamin D independence of the CaBPs in these putative new 1,25(OH)2D3 targets suggests the absence of an obligatory relationship between 1,25(OH)2D3 effects and CaBP induction therein.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of a set of calcium-binding proteins in reticuloplasm, the luminal content of the endoplasmic reticulum

1988 ◽  
Vol 91 (1) ◽  
pp. 61-70 ◽  
Author(s):  
D.R. Macer ◽  
G.L. Koch
Keyword(s):  
Endoplasmic Reticulum ◽  
Calcium Binding ◽  
Binding Proteins ◽  
Binding Capacity ◽  
Equilibrium Dialysis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Calcium Ionophore ◽  
Binding Activity ◽  
Calcium Binding Proteins ◽  
Molecular Weights

A procedure was developed for the isolation of reticuloplasm, the luminal material of the endoplasmic reticulum (ER). A reticuloplasm-rich extract was prepared from a murine plasmacytoma cell line that contains large amounts of ER, by first extracting the cytoplasmic contents using hypotonic lysis to yield ER-rich ‘shells’ followed by mechanical lysis to release the ER contents. The extract contains five major proteins with apparent molecular weights of 100, 75, 60, 58 and 55 (X 10(3] Mr by SDS-polyacrylamide gel electrophoresis. The 100, 75 and 58 (X 10(3] Mr species were identified as the known ER proteins endoplasmin, BiP and PD1, respectively. The ER association of the 60 and 55 (X 10(3] Mr proteins was confirmed by confocal fluorescence microscopy with affinity-purified antibodies. Equilibrium dialysis with isolated reticuloplasm gave a calcium-binding capacity of 300 nmoles calcium per mg protein with half-maximal binding at 3 mM-Ca2+. Purified endoplasmin bound 280 nmoles calcium per mg protein at a calcium concentration of 5 mM-Ca2+. A calcium overlay test revealed that, in addition to endoplasmin, reticuloplasm contained at least three other calcium-binding proteins: i.e. BiP, PDI and the 55 X 10(3) Mr protein, respectively, with endoplasmin and the 55 X 10(3) Mr protein (CRP55) accounting for the major proportion of the calcium-binding activity. Treatment of cells with calcium ionophore led to the specific over-expression of the major calcium-binding reticuloplasmins endoplasmin, BiP and CRP55. These studies show that the lumen of the ER contains a family of proteins with the capacity to bind significant amounts of calcium in the millimolar range and thereby to confer upon the ER the ability to perform a calcium storage function analogous to that of the sarcoplasmic reticulum in muscle cells.

How Important are S100A8/S100A9 Calcium Binding Proteins for the Activation of Phagocyte NADPH Oxidase, Nox2

2009 ◽  
Vol 8 (4) ◽  
pp. 282-289 ◽  
Author(s):  
Sylvie Berthier ◽  
Athan Baillet ◽  
Marie-Helene Paclet ◽  
Philippe Gaudin ◽  
Francoise Morel
Keyword(s):  
Nadph Oxidase ◽  
Calcium Binding ◽  
Binding Proteins ◽  
Calcium Binding Proteins ◽  
Phagocyte Nadph Oxidase
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