Cloning and expression of human TRAAK, a polyunsaturated fatty acids-activated and mechano-sensitive K+ channel

The two P domain hTRAAK K+ channel has been cloned from human brain. hTRAAK cDNA encodes a 393 amino acid polypeptide with 88% of homology with its mo use counterpart, The hTRAAK gene has been mapped to chromosome 11q13 and th e study of its organization indicates that the hTRAAK open reading frame is contained in six exons. hTRAAK is expressed abundantly in brain and placen ta, In COS cells, hTRAAK currents are K+-selective, instantaneous and non-i nactivating. These currents are insensitive to the classical K+ channels bl ockers 4-aminopyridine, tetraethylammonium, barium and quinidine, but are s trongly stimulated by application of arachidonic acid as well as other poly unsaturated fatty acids. hTRAAK can also be activated by a stretch of the m embrane. (C) 2000 Federation of European Biochemical Societies.