期刊
JOURNAL OF PHYSIOLOGY-LONDON
卷 555, 期 1, 页码 97-114出版社
WILEY
DOI: 10.1113/jphysiol.2003.053165
关键词
-
资金
- NIDDK NIH HHS [R21 DK062763, R01 DK051610, R21 DK062763-01, R01 DK51610] Funding Source: Medline
- NINDS NIH HHS [T32 NS07491, T32 NS007491] Funding Source: Medline
- PHS HHS [F32 G067424.01] Funding Source: Medline
CLH-3 is a meiotic cell cycle-regulated ClC Cl- channel that is functionally expressed in oocytes of the nematode Caenorhabditis elegans. CLH-3a and CLH-3b are alternatively spliced variants that have identical intramembrane regions, but which exhibit striking differences in their N- and C-termini. Structural and functional studies indicate that N- and C-terminal domains modulate ClC channel activity. We therefore postulated that alternative splicing of CLH-3 would alter channel gating and physiological functions. To begin testing this hypothesis, we characterized the biophysical properties of CLH-3a and CLH-3b expressed heterologously in HEK293 cells. CLH-3a activates more slowly and requires stronger hyperpolarization for activation than CLH-3b. Depolarizing conditioning voltages dramatically increase CLH-3a current amplitude and induce a slow inactivation process at hyperpolarized voltages, but have no significant effect on CLH-3b activity. CLH-3a also differs significantly in its extracellular Cl- and pH sensitivity compared to CLH-3b. Immunofluorescence microscopy demonstrated that CLH3b is translationally expressed during all stages of oocyte development, and furthermore, the biophysical properties of the native oocyte Cl- current are indistinguishable from those of heterologously expressed CLH-3b. We conclude that CLH-3b carries the oocyte Cl- current and that the channel probably functions in nonexcitable cells to depolarize membrane potential and/or mediate net Cl- transport. The unique voltage-dependent properties of CLH-3a suggest that the channel may function in muscle cells and neurones to regulate membrane excitability. We suggest that alternative splicing of CLH-3 N- and C-termini modifies the functional properties of the channel by altering the accessibility and/or function of pore-associated ion-binding sites.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据