scholarly journals Rapid purification and direct microassay of calbindin9kDa utilizing its solubility in perchloric acid

1993 ◽  
Vol 293 (1) ◽  
pp. 223-227 ◽  
Author(s):  
M J Hubbard

The 9 kDa calcium-binding protein, calbindin9kDa, was found to be soluble in 7% (v/v) perchloric acid. Calbindin9kDa was easily purified from rat duodenum in 1 day with perchloric acid precipitation followed by reverse-phase h.p.l.c. The yield was 21.4 +/- 2.3 nmol/g wet weight of tissue (mean +/- S.E.M.; n = 3) from normally fed 7-8-week-old rats (approx. 70% recovery). The purification was also effective with rabbit duodenum calbindin9kDa, but not with various other EF-hand calcium-binding proteins tested in the rat. Several criteria (h.p.l.c., u.v. spectrum, denaturing two-dimensional PAGE, N-terminal sequencing) indicated that the rat calbindin9kDa was purified to homogeneity and was not affected by proteolysis. High-affinity calcium-binding properties were retained and no evidence of isoforms or charge modification was observed. Residue 59, identified as Asn (not Asp as previously reported), was fully amidated. When adopted as a microassay with isocratic h.p.l.c., the perchloric acid procedure enabled rapid (less than 6 min) and direct (peptide bond absorbance) quantification of less than 1 pmol of calbindin9kDa. This new approach to purification and assay will be of particular utility for investigations of calbindin9kDa in previously intractable low-abundance sources (e.g. cultured cells).

2004 ◽  
Vol 167 (1) ◽  
pp. 87-98 ◽  
Author(s):  
Rebecca L. Frederick ◽  
J. Michael McCaffery ◽  
Kyle W. Cunningham ◽  
Koji Okamoto ◽  
Janet M. Shaw

Cell signaling events elicit changes in mitochondrial shape and activity. However, few mitochondrial proteins that interact with signaling pathways have been identified. Candidates include the conserved mitochondrial Rho (Miro) family of proteins, which contain two GTPase domains flanking a pair of calcium-binding EF-hand motifs. We show that Gem1p (yeast Miro; encoded by YAL048C) is a tail-anchored outer mitochondrial membrane protein. Cells lacking Gem1p contain collapsed, globular, or grape-like mitochondria. We demonstrate that Gem1p is not an essential component of characterized pathways that regulate mitochondrial dynamics. Genetic studies indicate both GTPase domains and EF-hand motifs, which are exposed to the cytoplasm, are required for Gem1p function. Although overexpression of a mutant human Miro protein caused increased apoptotic activity in cultured cells (Fransson et al., 2003. J. Biol. Chem. 278:6495–6502), Gem1p is not required for pheromone-induced yeast cell death. Thus, Gem1p defines a novel mitochondrial morphology pathway which may integrate cell signaling events with mitochondrial dynamics.


Author(s):  
Ariaki Nagayama

Vinblastine(Vb) or vincristine, alkaloid derived from Vinca rosea is known for its antimitotic activity by regrouping of microtubules into paracrystalline form within the cells. A rapid purification method of vinblastine-induced microtubular paracrystals(PC) has provided us with a fresh and pure microtubular material demonstrating the presence of a labile ATPase associated with the PC. The present report is concerned with the fine structure of purified microtubules of mammalian cultured cells.Confluent monolayer cultures of L cells were incubated for 20hrs with 10-5 M Vb (donated from Shionogi Seiyaku & Co., Osaka, Japan).


1986 ◽  
Vol 34 (2) ◽  
pp. 277-280 ◽  
Author(s):  
M Warembourg ◽  
O Tranchant ◽  
C Perret ◽  
C Desplan ◽  
M Thomasset

We have previously described the molecular cloning of a cDNA fragment synthesized from rat duodenal mRNA coding for a 9000-dalton vitamin D-induced calcium-binding protein (9-kDa CaBP) (3). We now report the use of this cloned cDNA to study the cytological distribution of 9-kDa CaBP mRNA in rat duodenum by in situ hybridization. Tissue sections, fixed in ethanol:acetic acid, were hybridized to the 3H-cDNA probe and processed for autoradiography. The specificity of the CaBP mRNA-DNA hybrid formation was checked using 3H-labeled plasmid pBR322 DNA as a control probe. 9k-Da CaBP mRNA, visualized by silver grains, was found only in the absorptive epithelial cells, and the concentration was greater in the cells at the villous tips than in those of the crypts. The 9k-Da CaBP mRNA was observed mainly in the cytoplasm of the columnar cells and less frequently in the nucleus. Labeling was not seen in the brush border and goblet cells. The submucosa, with Brunner's glands and muscularis, also showed no specific 9-kDa CaBP mRNA concentration. This demonstration of 9-kDa CaBP gene activity in the columnar cells of the rat duodenum illustrates the usefulness of in situ hybridization for characterization of specific cells involved in the expression of 1,25(OH)2 D3 activity.


1998 ◽  
Vol 550 ◽  
Author(s):  
Y. Senuma ◽  
S. Franceschin ◽  
J. G. Hilborn ◽  
P. Tissiéres ◽  
P. Frey

AbstractA new approach to the vesico-ureteral reflux could be a local regeneration of the defective vesicoureteral junction by transplanting living cells to the target site. The aim of this work is to provide a long-term effective treatment by producing bioresorbable microspheres which can act as support matrix for those cells, with the goal of an in vivo transfer of the in vitro cultured cells with a minimal surgical procedure. After microsphere degradation, the cells should be integrated into the muscular structure of the junction. Most innovative is that these are cultured muscle and urothelial cells from the bladder of the same patient.


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