High impact information on STRONTIUM

• Ca(2+) induces binding of the synaptotagmin C(2) domains to SNARE proteins, whereas Sr(2+) even at high concentrations does not [1].
• Thus, triggering of the fast component of release by Sr(2+) as a Ca(2+) agonist involves the formation of synaptotagmin/phospholipid complexes, but does not require stimulated SNARE binding [1].
• This was extended to PC12 cell exocytosis triggered by Sr(2+), which was also selectively affected by high-affinity C2-domains of synaptotagmins [2].
• We tested how switching divalent charge carriers from Ca(2+) to Sr(2+) and Ba(2+) affected Syn1A and synaptotagmin modulation of Ca(2+)-channel activation [3].
• Strontium ion formed DNA-phosphate precipitates analogous to those formed by calcium but lacking the lethal and differentiation-inducing effects of calcium on many epithelial cell types in primary culture [4].

Biological context of STRONTIUM

• However, Sr(2+) cannot substitute for Ca(2+) to support nucleotide hydrolysis, presumably because Sr(2+) cannot substitute for Ca(2+) in its second role as a nucleotide cosubstrate [5].
• It is not known whether Sr(2+) can replace Ca(2+) in small G protein-mediated sensitization of phosphorylation [6].
• When Sr(2+) substituted for Ca(2+), nerve-evoked synchronous synaptic transmission was severely depressed and delayed asynchronous release was appreciably increased in control embryos [7].
• The uptake of Sr(2+) by the whole body, gills and blood increased with temperature and showed saturation kinetics with the increase of Sr(2+) activity [8].
• The effect of Sr(2+) ions on the formation of quadruplex structures by the human telomere sequence d(TTAGGG)(4) is stronger and different from that of the other ions tested [9].

Anatomical context of STRONTIUM

• Sr(2+) depolarized mitochondria but failed to induce swelling [10].
• In the absence of membranes, the degree of apparent positive cooperativity in binding of Ca(2+), Sr(2+), and Ba(2+) decreased with increasing cation size, suggesting that the C2 domain binds two Ca(2+) or Sr(2+) ions, but only one Ba(2+) ion [11].
• In Jurkat and human peripheral blood T-lymphocytes, 1-oleoyl-2-acetyl-sn-glycerol (OAG), a membrane-permeant analogue of diacylglycerol, activated the influx of Ca(2+), Ba(2+) and Sr(2+) [12].
• This problem was overcome when the sperm-injected oocytes were treated with a parthenogenetic agent, Sr(2+) [13].
• Spermatozoa incubated overnight in the presence of Sr(2+) were unable to undergo the AR when exposed to hFF [14].

Associations of STRONTIUM with other chemical compounds

• Trp1-expressing cells displayed only modest carbachol-induced Ca(2+) entry and lacked OAG-induced Sr(2+) entry, whereas Trp3-expressing cells responded to both agents with a substantial divalent cation entry [15].
• The Sr(2+)- and Ca(2+)-containing enzymes were compared using EPR spectroscopy, UV-visible absorption spectroscopy, and O2 polarography [16].
• Furthermore, TRPM7 allows other essential metals such as Mn(2+) and Co(2+) to permeate, and permits significant entry of nonphysiologic or toxic metals such as Cd(2+), Ba(2+), and Sr(2+) [17].
• Large changes in SPR signals were observed for Sr(2+), Ba(2+), Cd(2+), and Mn(2+) as well as Ca(2+), indicating that upon binding to these ions, recoverin underwent a large conformational change to extrude the myristoyl group, and thereby interacted with lipid membranes [18].
• Here, crystal structures determined to 1.8 A resolution, both with Mg(2+) as the sole divalent counterion and with Mg(2+) and Sr(2+) (which mimics Pb(2+) with respect to binding but not catalysis), reveal the metal ion interactions with both the ground state and precatalytic conformations of the leadzyme [19].

Gene context of STRONTIUM

• HTRP3 antisense reduced, while HTRP1 antisense had no effect on, OAG-induced Sr(2+) entry [20].
• Expression of HTRP4 antisense inhibited 35% of the carbachol (CCh)-stimulated Ba(2+) entry and 46% of the OAG-stimulated Sr(2+) entry but in contrast had no effect on the thapsigargin-stimulated Ba(2+) or Sr(2+) entry [20].
• Here, crystallization of EMR2 in the presence of Ca(2+), Ba(2+) and Sr(2+) ions is reported [21].
• To discriminate between pre- and postsynaptic effects of ethanol on N-methyl-d-aspartate receptor (NMDAR) signaling in hippocampus, we adapted the technique of Sr(2+) substitution to the hippocampal blind slice patch-clamp preparation [22].
• The interaction of human visinin-like protein 1 (VILIP1) and visinin-like protein 3 (VILIP3) with divalent cations (Mg(2+), Ca(2+), Sr(2+) and Ba(2+)) was explored using circular dichroism and fluorescence measurement [23].

Analytical, diagnostic and therapeutic context of STRONTIUM

• Leaching of Sr(2+) and Cs(+), which were added to the cement to simulate immobilization of the corresponding radioisotopes, was also monitored [24].
• We carried out ICSI and ROSI every 20 min for up to 4 h after the activation of mouse oocytes by Sr(2+) and compared the late-stage development of ICSI- and ROSI- treated oocytes, including the formation of pronuclei, blastocyst formation, and offspring production [25].
• To avoid contamination of Ca(2+) from the cell wall and vacuole, the vacuolar sap was replaced with a sorbitol solution containing Sr(2+) by the vacuolar perfusion method after the cell had been treated with Sr(2+) [26].
• However, microarray analysis of gene expression at the eight-cell stage showed that activation by Sr(2+) leads to a distinct pattern of gene expression from that seen with embryos activated by cycloheximide [27].

References