title: Real time measures of prestin charge and fluorescence during plasma membrane trafficking reveal sub-tetrameric activity.
abstract: Prestin (SLC26a5) is the outer hair cell integral membrane motor protein that drives cochlear amplification, and has been described as an obligate tetramer. We studied in real time the delivery of YFP-prestin to the plasma membrane of cells from a tetracycline-inducible cell line. Following the release of temperature block to reinstate trans Golgi network delivery of the integral membrane protein, we measured nonlinear capacitance (NLC) and membrane fluorescence during voltage clamp. Prestin was delivered exponentially to the plasma membrane with a time constant of less than 10 minutes, with both electrical and fluorescence methods showing high temporal correlation. However, based on disparity between estimates of prestin density derived from either fluorescence or NLC, we conclude that sub-tetrameric forms of prestin contribute to our electrical and fluorescence measures. Thus, in agreement with previous observations we find that functional prestin is not an obligate tetramer.
authors.affiliation: Department of Surgery (Otolaryngology), Yale University School of Medicine, New Haven, Connecticut, United States of America.
authors.forename: Shumin
authors.initials: S
authors.lastname: Bian
authors.forename: Dhasakumar
authors.initials: D
authors.lastname: Navaratnam
authors.forename: Joseph
authors.initials: J
authors.lastname: Santos-Sacchi
mesh_terms: D027321:Anion Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D025802:Electric Capacitance; D004594:Electrophysiology; D005453:Fluorescence; D057809:HEK293 Cells; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D000076988:Sulfate Transporters; D021601:trans-Golgi Network / Q000378:metabolism*
chemical_list: D027321:Anion Transport Proteins; D001426:Bacterial Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; C498719:SLC26A5 protein, human; D000076988:Sulfate Transporters; C054562:yellow fluorescent protein, Bacteria