Phosphatidic acids mediate transport of Ca2+ and H+ through plant cell membranes

2019 ◽  
Vol 46 (6) ◽  
pp. 533 ◽  
Author(s):  
Sergei Medvedev ◽  
Olga Voronina ◽  
Olga Tankelyun ◽  
Tatiana Bilova ◽  
Dmitry Suslov ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Membranes ◽  
Acyl Chain ◽  
Central Element ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Phosphatidic Acids ◽  
Transport Of Ions ◽  
Membrane Bending ◽  
Plant Cell Membranes

Phosphatidic acids (PAs) are a key intermediate in phospholipid biosynthesis, and a central element in numerous signalling pathways. Functions of PAs are related to their fundamental role in molecular interactions within cell membranes modifying membrane bending, budding, fission and fusion. Here we tested the hypothesis that PAs are capable of direct transport of ions across bio-membranes. We have demonstrated that PAs added to the maize plasma membrane vesicles induced ionophore-like transmembrane transport of Ca2+, H+ and Mg2+. PA-induced Ca2+ fluxes increased with an increasing PAs acyl chain unsaturation. For all the PAs analysed, the effect on Ca2+ permeability increased with increasing pH (pH 8.0>pH 7.2>pH 6.0). The PA-induced Ca2+, Mg2+ and H+ permeability was also more pronounced in the endomembrane vesicles as compared with the plasma membrane vesicles. Addition of PA to protoplasts from Arabidopsis thaliana (L.) Heynh. roots constitutively expressing aequorin triggered elevation of the cytosolic Ca2+ activity, indicating that the observed PA-dependent Ca2+ transport occurs in intact plants.

Calcium efflux of plasma membrane vesicles exposed to ELF magnetic fields-test of a nuclear magnetic resonance interaction model

2012 ◽  
Vol 33 (7) ◽  
pp. 535-542 ◽  
Author(s):  
Wenjun J. Sun ◽  
Mehri Kaviani Mogadam ◽  
Marianne Sommarin ◽  
Henrietta Nittby ◽  
Leif G. Salford ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Plasma Membrane ◽  
Magnetic Resonance ◽  
Magnetic Fields ◽  
Interaction Model ◽  
Membrane Vesicles ◽  
Resonance Interaction ◽  
Calcium Efflux ◽  
Plasma Membrane Vesicles ◽  
Nuclear Magnetic

Pore-Spanning Plasma Membranes Derived from Giant Plasma Membrane Vesicles

2021 ◽  
Author(s):  
Nikolas K. Teiwes ◽  
Ingo Mey ◽  
Phila C. Baumann ◽  
Lena Strieker ◽  
Ulla Unkelbach ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles

scholarly journals Albumin binding of unconjugated [3H]bilirubin and its uptake by rat liver basolateral plasma membrane vesicles

1996 ◽  
Vol 316 (3) ◽  
pp. 999-1004 ◽  
Author(s):  
Lorella PASCOLO ◽  
Savino DEL VECCHIO ◽  
Ronald K. KOEHLER ◽  
J. Enrique BAYON ◽  
Cecile C. WEBSTER ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Basolateral Membrane ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Experimental Conditions ◽  
Saturation Kinetics ◽  
Basolateral Plasma Membrane ◽  
Component C ◽  
Uptake Studies

Using highly purified unconjugated [3H]bilirubin (UCB), we measured UCB binding to delipidated human serum albumin (HSA) and its uptake by basolateral rat liver plasma membrane vesicles, in both the absence and presence of an inside-positive membrane potential. Free UCB concentrations ([Bf]) were calculated from UCB–HSA affinity constants (K´f), determined by five cycles of ultrafiltration through a Centricon-10 device (Amicon) of the same solutions used in the uptake studies. At HSA concentrations from 12 to 380 μM, K´f (litre/mol) was inversely related to [HSA], irrespective of the [Bt]/[HSA] ratio. K´f was 2.066×106+(3.258×108/[HSA]). When 50 mM KCl was iso-osmotically substituted for sucrose, the K´f value was significantly lower {2.077×106+(1.099×108/[HSA])}. The transport occurred into an osmotic-sensitive space. Below saturation ([Bf] ⩽ 65 nM), both electroneutral and electrogenic components followed saturation kinetics with respect to [Bf], with Km values of 28±7 and 57±8 nM respectively (mean±S.D., n = 3, P < 0.001). The Vmax was greater for the electrogenic than for the electroneutral component (112±12 versus 45±4 pmol of UCB·mg-1 of protein·15 s-1, P < 0.001). Sulphobromophthalein trans-stimulated both electrogenic (61%) and electroneutral (72%) UCB uptake. These data indicate that: (a) as [HSA] increases, K´f decreases, thus increasing the concentration of free UCB. This may account for much of the enhanced hepatocytic uptake of organic anions observed with increasing [HSA]. (b) UCB is taken up at the basolateral membrane of the hepatocyte by two systems with Km values within the range of physiological free UCB levels in plasma. The electrogenic component shows a lower affinity and a higher capacity than the electroneutral component. (c) It is important to calculate the actual [Bf] using a K´f value determined under the same experimental conditions (medium and [HSA]) used for the uptake studies.

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