title: Essential helix interactions in the anion transporter domain of prestin revealed by evolutionary trace analysis.
abstract: Prestin, a member of the SLC26A family of anion transporters, is a polytopic membrane protein found in outer hair cells (OHCs) of the mammalian cochlea. Prestin is an essential component of the membrane-based motor that enhances electromotility of OHCs and contributes to frequency sensitivity and selectivity in mammalian hearing. Mammalian cells expressing prestin display a nonlinear capacitance (NLC), widely accepted as the electrical signature of electromotility. The associated charge movement requires intracellular anions reflecting the membership of prestin in the SLC26A family. We used the computational approach of evolutionary trace analysis to identify candidate functional (trace) residues in prestin for mutational studies. We created a panel of mutations at each trace residue and determined membrane expression and nonlinear capacitance associated with each mutant. We observe that several residue substitutions near the conserved sulfate transporter domain of prestin either greatly reduce or eliminate NLC, and the effect is dependent on the size of the substituted residue. These data suggest that packing of helices and interactions between residues surrounding the "sulfate transporter motif" is essential for normal prestin activity.
authors.affiliation: Department of Molecular Virology, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: Lavanya
authors.initials: L
authors.lastname: Rajagopalan
authors.forename: Nimish
authors.initials: N
authors.lastname: Patel
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Madabushi
authors.forename: Julie Anne
authors.initials: JA
authors.lastname: Goddard
authors.forename: Venkat
authors.initials: V
authors.lastname: Anjan
authors.forename: Feng
authors.initials: F
authors.lastname: Lin
authors.forename: Cindy
authors.initials: C
authors.lastname: Shope
authors.forename: Brenda
authors.initials: B
authors.lastname: Farrell
authors.forename: Olivier
authors.initials: O
authors.lastname: Lichtarge
authors.forename: Amy L
authors.initials: AL
authors.lastname: Davidson
authors.forename: William E
authors.initials: WE
authors.lastname: Brownell
authors.forename: Fred A
authors.initials: FA
authors.lastname: Pereira
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D027321:Anion Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D019020:Directed Molecular Evolution / Q000379:methods*; D019143:Evolution, Molecular; D005849:Gerbillinae; D006801:Humans; D008969:Molecular Sequence Data; D027361:Organic Anion Transporters / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D025941:Protein Interaction Mapping; D017433:Protein Structure, Secondary / Q000235:genetics; D048790:Renilla; D013329:Structure-Activity Relationship; D000076988:Sulfate Transporters
chemical_list: D027321:Anion Transport Proteins; D027361:Organic Anion Transporters; C498719:SLC26A5 protein, human; D000076988:Sulfate Transporters