R125H, W240S, C386R, and V507I SLC4A11 mutations associated with corneal endothelial dystrophy affect the transporter function but not trafficking in PS120 cells

Shimin Li, Karmjot Singh Hundal, Xingjuan Chen, Moonjung Choi, Diego G. Ogando, Alexander Obukhov, Joseph A. Bonanno

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

SLC4A11 mutations are associated with Fuchs’ endothelial corneal dystrophy (FECD), congenital hereditary endothelial dystrophy (CHED) and Harboyan syndrome (endothelial dystrophy with auditory deficiency). Mice with genetically ablated Slc4a11 recapitulate CHED, exhibiting significant corneal edema and altered endothelial morphology. We recently demonstrated that SLC4A11 functions as an NH3 sensitive, electrogenic H+ transporter. Here, we investigated the properties of five clinically relevant SLC4A11 mutants: R125H, W240S, C386R, V507I and N693A, relative to wild type, expressed in a PS120 fibroblast cell line. The effect of these mutations on the NH4Cl-dependent transporter activity was investigated by intracellular pH and electrophysiology measurements. Relative to plasma membrane expression of Na–K ATPase, there were no significant differences in plasma membrane SLC4A11 expression among each mutant and wild type. All mutants revealed a marked decrease in acidification in response to NH4Cl when compared to wild type, indicating a decreased H+ permeability in mutants. All mutants exhibited significantly reduced H+ currents at negative holding potentials as compared to wild type. Uniquely, the C386R and W240S mutants exhibited a different inward current profile upon NH4Cl challenges, suggesting an altered transport mode. Thus, our data suggest that these SLC4A11 mutants, rather than having impaired protein trafficking, show altered H+ flux properties.

Original languageEnglish (US)
Pages (from-to)86-91
Number of pages6
JournalExperimental Eye Research
Volume180
DOIs
StatePublished - Mar 1 2019

Fingerprint

Fuchs' Endothelial Dystrophy
Cell Membrane
Corneal Edema
Mutation
Electrophysiology
Protein Transport
Adenosine Triphosphatases
Permeability
Fibroblasts
Cell Line
Corneal dystrophy and perceptive deafness

Keywords

  • Ammonia
  • Intracellular pH
  • Patch clamp
  • Proton flux
  • SLC4A11

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

R125H, W240S, C386R, and V507I SLC4A11 mutations associated with corneal endothelial dystrophy affect the transporter function but not trafficking in PS120 cells. / Li, Shimin; Hundal, Karmjot Singh; Chen, Xingjuan; Choi, Moonjung; Ogando, Diego G.; Obukhov, Alexander; Bonanno, Joseph A.

In: Experimental Eye Research, Vol. 180, 01.03.2019, p. 86-91.

Research output: Contribution to journalArticle

Li, Shimin ; Hundal, Karmjot Singh ; Chen, Xingjuan ; Choi, Moonjung ; Ogando, Diego G. ; Obukhov, Alexander ; Bonanno, Joseph A. / R125H, W240S, C386R, and V507I SLC4A11 mutations associated with corneal endothelial dystrophy affect the transporter function but not trafficking in PS120 cells. In: Experimental Eye Research. 2019 ; Vol. 180. pp. 86-91.
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abstract = "SLC4A11 mutations are associated with Fuchs’ endothelial corneal dystrophy (FECD), congenital hereditary endothelial dystrophy (CHED) and Harboyan syndrome (endothelial dystrophy with auditory deficiency). Mice with genetically ablated Slc4a11 recapitulate CHED, exhibiting significant corneal edema and altered endothelial morphology. We recently demonstrated that SLC4A11 functions as an NH3 sensitive, electrogenic H+ transporter. Here, we investigated the properties of five clinically relevant SLC4A11 mutants: R125H, W240S, C386R, V507I and N693A, relative to wild type, expressed in a PS120 fibroblast cell line. The effect of these mutations on the NH4Cl-dependent transporter activity was investigated by intracellular pH and electrophysiology measurements. Relative to plasma membrane expression of Na–K ATPase, there were no significant differences in plasma membrane SLC4A11 expression among each mutant and wild type. All mutants revealed a marked decrease in acidification in response to NH4Cl when compared to wild type, indicating a decreased H+ permeability in mutants. All mutants exhibited significantly reduced H+ currents at negative holding potentials as compared to wild type. Uniquely, the C386R and W240S mutants exhibited a different inward current profile upon NH4Cl challenges, suggesting an altered transport mode. Thus, our data suggest that these SLC4A11 mutants, rather than having impaired protein trafficking, show altered H+ flux properties.",
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