En Block C-terminal Charge Cluster Reversals in Prestin (Slc26a5): Effects on Voltage-dependent Electromechanical Activity.
From: Neurology and Neurobiology, Yale University School of Medicine, New Haven, CT 06510, USA.
Neuroscience letters
- Publish Date: Sep 2006
- ISSN: 0304-3940
- Volume: 404
- Issue: 3
- Pages: 270-5
- Medium: Print
- Language: English
- Citation (JAMA): Bai Jun-Ping, Navaratnam Dhasakumar, Samaranayake Haresha, et al. En Block C-terminal Charge Cluster Reversals in Prestin (Slc26a5): Effects on Voltage-dependent Electromechanical Activity.. Neurosci. Lett. Sep 2006;404:270-5
Abstract
Prestin, the transmembrane motor protein is a novel protein underlying the motility of the outer hair cells. Nonlinear capacitance (NLC) or gating charge current, which can be observed in both auditory and transfected non-auditory cells, is the electrical signature of prestin’s electromechanical activity. To test the functional role of the C-terminus of prestin, several charged residue clusters were reversed en-block by site-directed mutagenesis. They are D/E to K at 516, 518, 522, 524, 527, 528 and 531 (cluster a); R/K to D at 571, 572, 573, 576, 577 and 580 (cluster b); R to D at 571; and E/D to K at 608, 609, 610, 611, 612 and 613 (cluster c). These constructs were transfected into Chinese hamster ovary cells (CHO) and NLC recordings were performed to evaluate the effects of these charge substitutions. All of the mutants showed NLC. Charge cluster a reversal significantly reduced the maximum charge movement (Qmax). All but one mutation (charge cluster c reversal) shifted V(h), indicative of the operating voltage range, in the depolarizing direction. None of the mutations affected unitary charge movement (z). These data suggest that the C-terminus of prestin lies outside the membrane voltage field, and may play an important role in controlling the operating voltage range through control of the protein’s conformational energy profile via allosteric means.
Mesh Headings (Keywords): Amino Acid Sequence, Animals, Biomechanics, CHO Cells, Cell Size, Cricetinae, Cricetulus, Electricity, Gerbillinae, Molecular Motor Proteins, Molecular Sequence Data, Mutagenesis, Site-Directed, Patch-Clamp Techniques
Check for Full Text / PubMed Unique Identifier (PMID): 16839688
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