Z P Sun

Publications (2)29.47 Total impact

• Article: Distribution of Ca2+-activated K+ channel isoforms along the tonotopic gradient of the chicken's cochlea.

  K P Rosenblatt, Z P Sun, S Heller, A J Hudspeth
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  ABSTRACT: In some cochleae, the number and kinetic properties of Ca2+-activated K+ (KCa) channels partly determine the characteristic frequency of each hair cell and thus help establish a tonotopic map. In the chicken's basilar papilla, we found numerous isoforms of KCa channels generated by alternative mRNA splicing at seven sites in a single gene, cSlo. In situ polymerase chain reactions demonstrated cSlo expression in hair cells and revealed differential distributions of KCa channel isoforms along the basilar papilla. Analysis of single hair cells by the reverse transcription polymerase chain reaction confirmed the differential expression of channel variants. Heterologously expressed cSlo variants differed in their sensitivities to Ca2+ and voltage, suggesting that the distinct spatial distributions of cSlo variants help determine the tonotopic map.
  Neuron 12/1997; 19(5):1061-75. · 14.74 Impact Factor
• Source

  Available from: Myles H Akabas

  Article: Exposure of residues in the cyclic nucleotide-gated channel pore: P region structure and function in gating.

  Z P Sun, M H Akabas, E H Goulding, A Karlin, S A Siegelbaum
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  ABSTRACT: In voltage-gated ion channels and in the homologous cyclic nucleotide-gated (CNG) channels, the loop between the S5 and S6 transmembrane segments (P region) is thought to form the lining of the pore. To investigate the structure and the role in gating of the P region of the bovine retinal CNG channel, we determined the accessibility of 11 cysteine-substituted P region residues to small, charged sulfhydryl reagents applied to the inside and outside of membrane patches in the open and closed states of the channel. The results suggest that the P region forms a loop that extends toward the central axis of the channel, analogous to the L3 loop of bacterial porin channels. Furthermore, the P region, in addition to forming the ion selectivity filter, functions as the channel gate, the structure of which changes when the channel opens.
  Neuron 02/1996; 16(1):141-9. · 14.74 Impact Factor