Do we know the absolute values of intracellular free calcium concentration?
| Autor: | Ryszard Grygorczyk, Sergei V. Kotelevtsev, Sergei N. Orlov |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Intracellular Fluid
Calmodulin Physiology Analytical chemistry chemistry.chemical_element Calcium-Transporting ATPases Calcium Troponin C chemistry.chemical_compound Chelation Egtazic Acid Molecular Biology Chelating Agents Fluorescent Dyes Calcium metabolism biology Chemistry Endoplasmic reticulum Cell Membrane Cell Biology Reference Standards Sarcoplasmic Reticulum EGTA Aminoquinolines biology.protein Biophysics Indicators and Reagents Intracellular |
| Zdroj: | Cell Calcium. 34:511-515 |
| ISSN: | 0143-4160 |
| DOI: | 10.1016/s0143-4160(03)00125-8 |
| Popis: | More than 20 years ago, it was shown that the addition of EGTA increases the affinity of the plasma membrane Ca2+ pump for Ca2+ by an order of magnitude. The left-hand shift of Ca2+-dependencies in the presence of EGTA has been also documented in studies of the sarcoplasmic reticulum Ca2+ pump, mitochondrial Ca2+-transporter as well as Ca2+-binding by calmodulin and troponin C. These data allow us to hypothesise that this effect is caused by an admixture of di- and trivalent cations possessing high affinity for EGTA and interacting with Ca2+-transporting and binding proteins. Here, we propose that polyvalent cations affect the estimation of absolute values of free intracellular Ca2+ concentration. Indeed, EGTA sharply increases the apparent affinity of the fluorescent Ca2+ indicators quin-2 and fluo-3 for Ca2+. The impact of polyvalent cations on Ca2+ measurement was further confirmed by the study showing the high sensitivity of Ca2+-induced fluo-3 fluorescence to Mn2+, Fe2+, Cu2+, and Co2+ seen in the absence of EGTA. |
| Databáze: | OpenAIRE |
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