Molecular cloning and partial functional characterization of Tsha3--a novel modulatory potassium channel alpha-subunit of trout CNS.
A novel Shaker-related potassium channel subunit termed Tsha3 that is widely expressed in the CNS of trout was PCR-cloned and sequenced: its deduced amino acid sequence showed an extended N-terminal domain with a high proportion of negatively charged residues and possessed highest similarity with KCNA10, a human epithelial potassium channel. Upon heterologous expression in Sf21 cells, homomeric Tsha3 did not yield voltage-activated potassium channels but produced only ohmic currents that reversed at -15 mV. After co-expression with Tsha1, a novel outward rectifier current was generated that differed from homomeric Tsha1 by its slower kinetics of activation, its partial current inactivation, and its partial blockade by 5 mM TEA as well as 1 microM DTX. Co-immunoprecipitation studies using anti-Tsha3 antibodies confirmed that Tsha3 tightly bound with Tsha1 in co-infected Sf21 cells. As revealed from GFP- and DsRed-labeling studies, the pattern of distribution of Tsha1 was profoundly altered after co-infection with Tsha3 subunits.
Piwowarski
Tanja
T
Department of Neurobiology, University of Osnabrück, Barbarastr. 11, 49069 Osnabrück, Germany.
Panofen
Frank
F
Jeserich
Gunnar
G
D000818:Animals; D002490:Central Nervous System / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D019143:Evolution, Molecular; D007150:Immunohistochemistry; D008564:Membrane Potentials / Q000187:drug effects / Q000235:genetics; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D024642:Potassium Channels, Voltage-Gated; D011485:Protein Binding / Q000276:immunology; D017434:Protein Structure, Tertiary / Q000235:genetics; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D051637:Shaker Superfamily of Potassium Channels
D018076:DNA, Complementary; C460019:KCNA10 protein, human; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D021122:Protein Subunits; D051637:Shaker Superfamily of Potassium Channels