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18 July 2012 Variants of Stretch-Activated Two-Pore Potassium Channel TREK-1 Associated with Preterm Labor in Humans
Yi-Ying Wu, Cherie A. Singer, Iain L.O. Buxton
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Spontaneous preterm labor (PTL) is a uniquely human problem that results in preterm delivery of an underdeveloped fetus. The underlying cause remains elusive. The cost to societies in human suffering and treasure is enormous. The stretch-activated two pore potassium channel TREK-1 is up-regulated during gestation to term such that it may maintain uterine quiescence by hyperpolarizing the smooth muscle cell membrane. We have hypothesized that the human TREK-1 channel is involved in myometrial relaxation during pregnancy and that splice variants of the TREK-1 channel expressed in preterm myometrium are associated with preterm delivery by interaction with full-length TREK-1. We detected three wild-type human TREK-1 transcript isoforms in nonpregnant and pregnant human myometrium. Using RT-PCR, we identified five unique TREK-1 splice variants in myometrium from women in PTL. These myometrial TREK-1 variants lack either the pore or the transmembrane domains or both. In transiently transfected HEK293T cells, wild-type TREK-1 was predominantly expressed at the plasma membrane. However, individual splice variants were expressed uniformly throughout the cell. Wild-type TREK-1 was localized at the plasma membrane and cytoplasm close to the plasma membrane when coexpressed with each splice variant. Co-immunoprecipitation of FLAG epitope-tagged TREK-1 and six-His epitope-tagged splice variants using Ni bead columns successfully pulled down wild-type TREK-1. These results suggest that each of four TREK-1 splice variants interacts with full-length wild-type TREK-1 and that in vivo, such interactions may contribute to a PTL phenotype.

Yi-Ying Wu, Cherie A. Singer, and Iain L.O. Buxton "Variants of Stretch-Activated Two-Pore Potassium Channel TREK-1 Associated with Preterm Labor in Humans," Biology of Reproduction 87(4), (18 July 2012).
Received: 25 January 2012; Accepted: 1 July 2012; Published: 18 July 2012

myometrial smooth muscle
potassium channels
preterm labor
splice variants
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