TY - JOUR
T1 - Temperature-induced inactivation of cytoplasmic biogel osmosensing properties is associated with suppression of regulatory volume decrease in A549 cells
AU - Platonova, Alexandra
AU - Boudreault, Francis
AU - Kapilevich, Leonid V.
AU - Maksimov, Georgy V.
AU - Ponomarchuk, Olga
AU - Grygorczyk, Ryszard
AU - Orlov, Sergei N.
PY - 2014
Y1 - 2014
N2 - Upstream intermediates of intracellular signaling involved in cell volume regulation remain poorly explored. Recently, we demonstrated that osmolarity-induced volume changes in permeabilized cells were several-fold higher than those observed with intact cells, indicating the osmosensing properties of cytoplasmic gel. To further examine the role of cytoplasmic biogel in cell volume regulation, we compared the action of short-term heat treatment on volume changes in intact and permeabilized A549 cells. Pretreatment of A549 cells at 48 °C suppressed swelling triggered by dissipation of Donnan's equilibrium as well as by hyposmotic medium. Significantly, heat treatment completely abolished the action of hyposomotic medium on volume changes in permeabilized cells, showing that temperature elevation suppresses osmosensing properties via its effect on biogel rather than on plasma membrane water permeability. Identical heat treatment blocked the regulatory volume decrease (RVD) as well as the increment of Ba2+-sensitive K +-channel activity seen in control cells exposed to hyposmotic swelling. Unlike swelling, hyperosmotic shrinkage was decreased by twofold in cells subjected to 10-min preincubation at 50 °C. Our results disclose that osmosensing by cytoplasmic gel is a key event in the RVD triggered by hypotonic swelling. The role of biogel and plasma membrane in intracellular signaling triggered by hyperosmotic shrinkage should be further investigated.
AB - Upstream intermediates of intracellular signaling involved in cell volume regulation remain poorly explored. Recently, we demonstrated that osmolarity-induced volume changes in permeabilized cells were several-fold higher than those observed with intact cells, indicating the osmosensing properties of cytoplasmic gel. To further examine the role of cytoplasmic biogel in cell volume regulation, we compared the action of short-term heat treatment on volume changes in intact and permeabilized A549 cells. Pretreatment of A549 cells at 48 °C suppressed swelling triggered by dissipation of Donnan's equilibrium as well as by hyposmotic medium. Significantly, heat treatment completely abolished the action of hyposomotic medium on volume changes in permeabilized cells, showing that temperature elevation suppresses osmosensing properties via its effect on biogel rather than on plasma membrane water permeability. Identical heat treatment blocked the regulatory volume decrease (RVD) as well as the increment of Ba2+-sensitive K +-channel activity seen in control cells exposed to hyposmotic swelling. Unlike swelling, hyperosmotic shrinkage was decreased by twofold in cells subjected to 10-min preincubation at 50 °C. Our results disclose that osmosensing by cytoplasmic gel is a key event in the RVD triggered by hypotonic swelling. The role of biogel and plasma membrane in intracellular signaling triggered by hyperosmotic shrinkage should be further investigated.
KW - Cell volume
KW - Cytoplasmic biogel
KW - Permeabilized A549 cells
KW - Regulatory volume decrease
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U2 - 10.1007/s00232-014-9673-9
DO - 10.1007/s00232-014-9673-9
M3 - Article
C2 - 24840161
AN - SCOPUS:84903608003
VL - 247
SP - 571
EP - 579
JO - Journal of Membrane Biology
JF - Journal of Membrane Biology
SN - 0022-2631
IS - 7
ER -