Cell volume regulation in response to hypotonicity is impaired in HeLa cells expressing a protein kinase C alpha mutant lacking kinase activity
The chloride conductance (GCl,swell) that participates in the regulatory volume decrease process triggered by osmotic swelling in HeLa cells was impaired by removal of extracellular Ca2+, depletion of intracellular Ca2+ stores with thapsigargin, or by preloading the cells with BAPTA-AM (1,2-bis(2-aminophenoxy)ethane-N,N,N?,N? -tetraacetic acid). Furthermore, overnight exposure to the phorbol ester tetradecanoyl phorbol acetate and acute incubation with inhibitors of the conventional protein kinase C (PKC) isoforms bisindolylmaleimide I and Gö6976 inhibited GCl,swell. Treatment of HeLa cells with U73122, a phospholipase C inhibitor, also prevented GCl,swell. Hypotonicity induced selective PKC? accumulation in the membrane/cytoskeleton fraction in fractionation experiments and translocation of a green fluorescent protein-PKC? fusion protein to the plasma membrane of transiently transfected HeLa cells. To further explore the role of PKCs in hypotonicity-induced GCl,swell, HeLa clones stably expressing either a kinase-dead dominant negative variant of the Ca2+-dependent PKC isoform ? (PKC? K386R) or of the atypical PKC isoform ? (PKC? K275W) were generated. GCl,swell was significantly reduced in HeLa cells expressing the dominant negative PKC? mutant but remained unaltered in cells expressing dominant negative PKC?. These findings strongly implicate PKC? as a critical regulatory element that is required for efficient regulatory volume decrease in HeLa cells.
|Título según WOS:||Cell volume regulation in response to hypotonicity is impaired in HeLa cells expressing a protein kinase C alpha mutant lacking kinase activity|
|Título según SCOPUS:||Cell Volume Regulation in Response to Hypotonicity Is Impaired in HeLa Cells Expressing a Protein Kinase C? Mutant Lacking Kinase Activity|
|Título de la Revista:||JOURNAL OF BIOLOGICAL CHEMISTRY|
|Editorial:||AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC|
|Fecha de publicación:||2004|
|Página de inicio:||17681|