PMID- 11697081
OWN - NLM
STAT- MEDLINE
DCOM- 20020220
LR  - 20200825
IS  - 1060-6823 (Print)
IS  - 1060-6823 (Linking)
VI  - 7
IP  - 5
DP  - 2001
TI  - Primary structure, developmental expression and functional properties of an 
      inward rectifier K+ channel of the tunicate.
PG  - 387-99
AB  - A cDNA encoding for a tunicate inward rectifier K+ channel (TuIRK) was isolated. 
      TuIRK exhibited the highest similarity (approximately 50%) with mammalian Kir2 
      (IRK) subfamily. Maternal RNA of TuIRK was detected by RT-PCR in unfertilized 
      eggs. By in situ hybridization, the transcript was observed at the 32-cell stage, 
      restricted at the 64-cell stage in anterior epidermal cells of a4-2 blastomere 
      lineage, and disappeared at the late gastrula stage. Therefore, TuIRK was 
      identified to be the inward rectifier whose expression was previously reported to 
      change dramatically upon the neural/epidermal cell fate selection. In Xenopus 
      oocytes, TuIRK expressed a strongly inward rectifying K+ current. The basic 
      electrophysiological properties of TuIRK were similar to those of the mouse IRK1 
      (mIRK1), except that the sensitivity to the block by extracellular Mg2+ was much 
      lower than that of mIRK1. To identify the structural determinant, we made mutants 
      of the pore region, and then of the extracellular loop (N226 of TuIRK, and E125 
      of mIRK1). In E125N mutant of mIRK1, the sensitivity to the Mg2+ block was 
      decreased significantly, whereas N226E of TuIRK1 did not acquire the sensitivity. 
      These results demonstrate the contribution of this site to the Mg2+ block and the 
      presence of additional determinant(s).
FAU - Murata, Y
AU  - Murata Y
AD  - Department of Physiology, Tokyo Medical and Dental University, Graduate School 
      and Faculty of Medicine, D-566, Yushima 1-5-45, Bunkyo, Tokyo 113-8519, Japan.
FAU - Okado, H
AU  - Okado H
FAU - Katsuyama, Y
AU  - Katsuyama Y
FAU - Okamura, Y
AU  - Okamura Y
FAU - Kubo, Y
AU  - Kubo Y
LA  - eng
SI  - GENBANK/AB052084
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Recept Channels
JT  - Receptors & channels
JID - 9315376
RN  - 0 (Potassium Channels)
RN  - 0 (Potassium Channels, Inwardly Rectifying)
SB  - IM
MH  - Amino Acid Sequence
MH  - Animals
MH  - Electric Conductivity
MH  - Electrophysiology
MH  - Gene Library
MH  - Molecular Sequence Data
MH  - Mutation
MH  - Potassium Channels/genetics/*metabolism
MH  - *Potassium Channels, Inwardly Rectifying
MH  - Sequence Homology, Amino Acid
MH  - Tissue Distribution
MH  - Urochordata/genetics/*metabolism
EDAT- 2001/11/08 10:00
MHDA- 2002/02/21 10:01
CRDT- 2001/11/08 10:00
PHST- 2001/11/08 10:00 [pubmed]
PHST- 2002/02/21 10:01 [medline]
PHST- 2001/11/08 10:00 [entrez]
PST - ppublish
SO  - Recept Channels. 2001;7(5):387-99.