Conserved dimeric subunit stoichiometry of SLC26 multifunctional anion exchangers.
The SLC26 gene family encodes multifunctional transport proteins in numerous tissues and organs. Some paralogs function as anion exchangers, others as anion channels, and one, prestin (SLC26A5), represents a membrane-bound motor protein in outer hair cells of the inner ear. At present, little is known about the molecular basis of this functional diversity. We studied the subunit stoichiometry of one bacterial, one teleost, and two mammalian SLC26 isoforms expressed in Xenopus laevis oocytes or in mammalian cells using blue native PAGE and chemical cross-linking. All tested SLC26s are assembled as dimers composed of two identical subunits. Co-expression of two mutant prestins with distinct voltage-dependent capacitances results in motor proteins with novel electrical properties, indicating that the two subunits do not function independently. Our results indicate that an evolutionarily conserved dimeric quaternary structure represents the native and functional state of SLC26 transporters.
Detro-Dassen
Silvia
S
Abteilung Molekulare Pharmakologie, Rheinisch-Westfälische Technische Hochschule Aachen University, Wendlingweg 2, Aachen 52074, Germany.
Schänzler
Michael
M
Lauks
Heike
H
Martin
Ina
I
zu Berstenhorst
Sonja Meyer
SM
Nothmann
Doreen
D
Torres-Salazar
Delany
D
Hidalgo
Patricia
P
Schmalzing
Günther
G
Fahlke
Christoph
C
D000818:Animals; D027321:Anion Transport Proteins / Q000737:chemistry* / Q000502:physiology; D018118:Chloride Channels / Q000502:physiology; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D051381:Rats; D000076988:Sulfate Transporters; D014982:Xenopus laevis
D027321:Anion Transport Proteins; C086321:CLC-1 channel; D018118:Chloride Channels; C473560:SLC26A1 protein, human; C498719:SLC26A5 protein, human; D000076988:Sulfate Transporters