Abstract
pI(Cln) is found ubiquitously in mammalian cells and is postulated to play a critical role in cell volume regulation. Mutagenesis studies led to the proposal that pI(Cln) is a swelling-activated anion channel. However, recent studies in Madin-Darby canine kidney cells and endothelial cells have shown that the protein is localized primarily to the cytoplasm. It has therefore been postulated that activation involves reversible translocation of pI(Cln) from the cytoplasm and insertion into the plasma membrane. We tested this hypothesis using several different approaches. Fractionation of C6 glioma cells into plasma membrane- and cytoplasm-containing fractions demonstrated that ~90% of the recovered pI(Cln) was confined to the cytosol. Swelling had no effect on the relative amount of protein present in the plasma membrane fraction. Immunofluorescence microscopy revealed that pI(Cln) is localized primarily, if not exclusively, to the cytoplasm of swollen and nonswollen cells. Similarly, transfection of cells with a green fluorescent protein-labeled pI(Cln) construct failed to reveal any membrane localization of the protein. These findings do not support the hypothesis that pI(Cln) is a volume regulatory anion channel activated by swelling-induced membrane insertion.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Cell Physiology |
| Volume | 274 |
| Issue number | 6 43-6 |
| State | Published - Jun 1998 |
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Keywords
- Anion channels
- Cell volume regulation
- Organic osmolytes
- Osmoregulation
ASJC Scopus subject areas
- Clinical Biochemistry
- Cell Biology
- Physiology
- Physiology (medical)
Cite this
Effect of cell swelling on membrane and cytoplasmic distribution of pI(Cln). / Emma, Francesco; Breton, Sylvie; Morrison, Rebecca; Wright, Stephen; Strange, Kevin.
In: American Journal of Physiology - Cell Physiology, Vol. 274, No. 6 43-6, 06.1998.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effect of cell swelling on membrane and cytoplasmic distribution of pI(Cln)
AU - Emma, Francesco
AU - Breton, Sylvie
AU - Morrison, Rebecca
AU - Wright, Stephen
AU - Strange, Kevin
PY - 1998/6
Y1 - 1998/6
N2 - pI(Cln) is found ubiquitously in mammalian cells and is postulated to play a critical role in cell volume regulation. Mutagenesis studies led to the proposal that pI(Cln) is a swelling-activated anion channel. However, recent studies in Madin-Darby canine kidney cells and endothelial cells have shown that the protein is localized primarily to the cytoplasm. It has therefore been postulated that activation involves reversible translocation of pI(Cln) from the cytoplasm and insertion into the plasma membrane. We tested this hypothesis using several different approaches. Fractionation of C6 glioma cells into plasma membrane- and cytoplasm-containing fractions demonstrated that ~90% of the recovered pI(Cln) was confined to the cytosol. Swelling had no effect on the relative amount of protein present in the plasma membrane fraction. Immunofluorescence microscopy revealed that pI(Cln) is localized primarily, if not exclusively, to the cytoplasm of swollen and nonswollen cells. Similarly, transfection of cells with a green fluorescent protein-labeled pI(Cln) construct failed to reveal any membrane localization of the protein. These findings do not support the hypothesis that pI(Cln) is a volume regulatory anion channel activated by swelling-induced membrane insertion.
AB - pI(Cln) is found ubiquitously in mammalian cells and is postulated to play a critical role in cell volume regulation. Mutagenesis studies led to the proposal that pI(Cln) is a swelling-activated anion channel. However, recent studies in Madin-Darby canine kidney cells and endothelial cells have shown that the protein is localized primarily to the cytoplasm. It has therefore been postulated that activation involves reversible translocation of pI(Cln) from the cytoplasm and insertion into the plasma membrane. We tested this hypothesis using several different approaches. Fractionation of C6 glioma cells into plasma membrane- and cytoplasm-containing fractions demonstrated that ~90% of the recovered pI(Cln) was confined to the cytosol. Swelling had no effect on the relative amount of protein present in the plasma membrane fraction. Immunofluorescence microscopy revealed that pI(Cln) is localized primarily, if not exclusively, to the cytoplasm of swollen and nonswollen cells. Similarly, transfection of cells with a green fluorescent protein-labeled pI(Cln) construct failed to reveal any membrane localization of the protein. These findings do not support the hypothesis that pI(Cln) is a volume regulatory anion channel activated by swelling-induced membrane insertion.
KW - Anion channels
KW - Cell volume regulation
KW - Organic osmolytes
KW - Osmoregulation
UR - http://www.scopus.com/inward/record.url?scp=0031776508&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031776508&partnerID=8YFLogxK
M3 - Article
VL - 274
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6143
IS - 6 43-6
ER -