Cloning of a new XXXX two-P domain channel subunit and a @entity1 homologue with a unique pore structure.

@entity1 @entity65290 @entity19 @entity535 @entity65289 @entity141
@entity19 @entity65290 is a new subunit belonging to the TWIK channel family. This 335- @entity535 polypeptide has four transmembrane segments, two pore-forming domains, and a @entity141 -binding EF-hand motif. Expression of @entity65290 transcripts is principally observed in eyes, lung, stomach and embryo. In the eyes, immunohistochemistry reveals protein expression only in some of the retina neurons. Although @entity65290 is able to dimerize as other functional two-P domain K+ channels when it is expressed in COS-7 cells, it remains in the endoplasmic reticulum and is unable to generate ionic channel activity. Deletions, mutations, and chimera constructions suggest that @entity65290 is not an intracellular channel but rather a subunit that needs to associate with a partner, which remains to be discovered, in order to reach the plasma membrane. A closely related @entity1 @entity65289 -A subunit has been cloned. @entity65289 displays an intriguing GLE sequence in its filter region instead of the G(Y/F/L)G sequence, which is considered to be the K+ channel signature. This subunit is alternatively spliced and gives rise to the shorter forms @entity65289 -B and -C. None of the @entity65289 structures can generate channel activity by itself. The @entity65289 gene is situated on chromosome 11, in the q13 region, where several candidate diseases have been identified.
