Abstract
ClC-5 chloride channel deficiency causes proteinuria, hypercalciuria, and nephrolithiasis (Dent's disease). Impaired endosomal acidification in proximal tubule caused by reduced chloride conductance is a proposed mechanism; however, functional analysis of ClC-5 in oocytes predicts low ClC-5 chloride conductance in endosomes because of their acid interior pH and positive potential. Here, endosomal pH and chloride concentration were measured in proximal tubule cell cultures from wildtype vs. ClC-5 deficient mice using fluorescent sensors coupled to transferrin (early/recycling endosomes) or α2- macroglobulin (late endosomes). Initial pH in transferrin-labeled endosomes was ∼7.2, decreasing at 15 min to 6.0 vs. 6.5 in wildtype vs. ClC-5 deficient cells, respectively; corresponding endosomal chloride concentration increased from ∼16 mM to 47 vs. 36 mM. In contrast, acidification and chloride accumulation were not impaired in late endosomes or Golgi. Our results provide direct evidence for ClC-5 involvement in acidification of early endosomes in proximal tubule by a chloride shunt mechanism.
| Original language | English |
|---|---|
| Pages (from-to) | 941-946 |
| Number of pages | 6 |
| Journal | Biochemical and Biophysical Research Communications |
| Volume | 329 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 2005 Apr 15 |
| Externally published | Yes |
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Keywords
- Chloride transport
- Endocytosis
- Macroglobulin
- Ratioimaging
- Transferrin
ASJC Scopus subject areas
- Biochemistry
- Biophysics
- Molecular Biology
Cite this
Impaired acidification in early endosomes of ClC-5 deficient proximal tubule. / Chikuma, Mariko; Wang, Yinghong; Guggino, Sandra E.; Guggino, William B.; Verkman, A. S.
In: Biochemical and Biophysical Research Communications, Vol. 329, No. 3, 15.04.2005, p. 941-946.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Impaired acidification in early endosomes of ClC-5 deficient proximal tubule
AU - Chikuma, Mariko
AU - Wang, Yinghong
AU - Guggino, Sandra E.
AU - Guggino, William B.
AU - Verkman, A. S.
PY - 2005/4/15
Y1 - 2005/4/15
N2 - ClC-5 chloride channel deficiency causes proteinuria, hypercalciuria, and nephrolithiasis (Dent's disease). Impaired endosomal acidification in proximal tubule caused by reduced chloride conductance is a proposed mechanism; however, functional analysis of ClC-5 in oocytes predicts low ClC-5 chloride conductance in endosomes because of their acid interior pH and positive potential. Here, endosomal pH and chloride concentration were measured in proximal tubule cell cultures from wildtype vs. ClC-5 deficient mice using fluorescent sensors coupled to transferrin (early/recycling endosomes) or α2- macroglobulin (late endosomes). Initial pH in transferrin-labeled endosomes was ∼7.2, decreasing at 15 min to 6.0 vs. 6.5 in wildtype vs. ClC-5 deficient cells, respectively; corresponding endosomal chloride concentration increased from ∼16 mM to 47 vs. 36 mM. In contrast, acidification and chloride accumulation were not impaired in late endosomes or Golgi. Our results provide direct evidence for ClC-5 involvement in acidification of early endosomes in proximal tubule by a chloride shunt mechanism.
AB - ClC-5 chloride channel deficiency causes proteinuria, hypercalciuria, and nephrolithiasis (Dent's disease). Impaired endosomal acidification in proximal tubule caused by reduced chloride conductance is a proposed mechanism; however, functional analysis of ClC-5 in oocytes predicts low ClC-5 chloride conductance in endosomes because of their acid interior pH and positive potential. Here, endosomal pH and chloride concentration were measured in proximal tubule cell cultures from wildtype vs. ClC-5 deficient mice using fluorescent sensors coupled to transferrin (early/recycling endosomes) or α2- macroglobulin (late endosomes). Initial pH in transferrin-labeled endosomes was ∼7.2, decreasing at 15 min to 6.0 vs. 6.5 in wildtype vs. ClC-5 deficient cells, respectively; corresponding endosomal chloride concentration increased from ∼16 mM to 47 vs. 36 mM. In contrast, acidification and chloride accumulation were not impaired in late endosomes or Golgi. Our results provide direct evidence for ClC-5 involvement in acidification of early endosomes in proximal tubule by a chloride shunt mechanism.
KW - Chloride transport
KW - Endocytosis
KW - Macroglobulin
KW - Ratioimaging
KW - Transferrin
UR - http://www.scopus.com/inward/record.url?scp=14844293074&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=14844293074&partnerID=8YFLogxK
U2 - 10.1016/j.bbrc.2005.02.060
DO - 10.1016/j.bbrc.2005.02.060
M3 - Article
C2 - 15752747
AN - SCOPUS:14844293074
VL - 329
SP - 941
EP - 946
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 3
ER -