Variants of stretch-activated two-pore potassium channel TREK-1 associated with preterm labor in humans.
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.
Department of Pharmacology, University of Nevada School of Medicine, Reno, 89557, USA.
Yi-Ying
YY
Wu
Cherie A
CA
Singer
Iain L O
IL
Buxton
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D005260:Female; D056726:Genetic Association Studies; D057809:HEK293 Cells; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D007752:Obstetric Labor, Premature / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D024683:Potassium Channels, Tandem Pore Domain / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D011247:Pregnancy; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D055815:Young Adult
D024683:Potassium Channels, Tandem Pore Domain; D020033:Protein Isoforms; C103742:potassium channel protein TREK-1