Journal
JOURNAL OF BIOLOGICAL CHEMISTRY
Volume 295, Issue 6, Pages 1464-1473Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.RA119.011366
Keywords
electrophysiology; stoichiometry; epithelial cell; transporter; ion-sensitive electrode; Cl-?; H+ exchanger ClC-5; CLCN5; dent disease 1 (DD1); kidney disorder; Xenopus oocyte
Categories
Funding
- Rare Kidney Stone Consortium [U54 DK083908]
- NIDDK
- National Center For Advancing Translational Sciences (NCATS)
- Mayo Clinic O'Brien Urology Research Center Grant [U54 DK100227]
- Mayo Clinic nuSURF program [R25 DK101405]
- Mayo Foundation
Ask authors/readers for more resources
Dent disease 1 (DD1) is caused by mutations in the CLCN5 gene encoding a voltage-gated electrogenic nCl(?)/H+ exchanger ClC-5. Using ion-selective microelectrodes and Xenopus oocytes, here we studied Cl-?/H+ coupling properties of WT ClC-5 and four DD1-associated variants (S244L, R345W, Q629*, and T657S), along with trafficking and localization of ClC-5. WT ClC-5 had a 2Cl(?)/H+ exchange ratio at a V-h of +40 mV with a [Cl-?](out) of 104 mm, but the transport direction did not reverse with a [Cl-?](out) of 5 mm, indicating that ClC-5-mediated exchange of two Cl-? out for one H+ in is not permissible. We hypothesized that ClC-5 and H+-ATPase are functionally coupled during H+-ATPase?mediated endosomal acidification, crucial for ClC-5 activation by depolarizing endosomes. ClC-5 transport that provides three net negative charges appeared self-inhibitory because of ClC-5's voltage-gated properties, but shunt conductance facilitated further H+-ATPase?mediated endosomal acidification. Thus, an on-and-off ?burst? of ClC-5 activity was crucial for preventing Cl-? exit from endosomes. The subcellular distribution of the ClC-5:S244L variant was comparable with that of WT ClC-5, but the variant had a much slower Cl-? and H+ transport and displayed an altered stoichiometry of 1.6:1. The ClC-5:R345W variant exhibited slightly higher Cl-?/H+ transport than ClC-5:S244L, but co-localized with early endosomes, suggesting decreased ClC-5:R345W membrane trafficking is perhaps in a fully functional form. The truncated ClC-5:Q629* variant displayed the lowest Cl-?/H+ exchange and was retained in the endoplasmic reticulum and cis-Golgi, but not in early endosomes, suggesting the nonsense mutation affects ClC-5 maturation and trafficking.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available