Cloning a novel human brain inward rectifier potassium channel and its functional expression in Xenopus oocytes.
نویسندگان
چکیده
We have cloned a novel inward rectifier K+ channel (hIRK2) from a human frontal cortex cDNA library. The amino acid sequence of hIRK2 shares 60% and 40% identity with the mouse IRK1 and the rat ROMK1 channels, respectively. Xenopus oocytes injected with hIRK2 cRNA showed an inwardly rectifying K+ current that had a prominent 'N-shape' I-V curve and was blocked by extracellular Ba2+. The hIRK2 channel has two unique features: (a) an 18 amino acid insertion between the first transmembrane region and the pore, and (b) restricted mRNA distribution found only in human brain and heart.
منابع مشابه
Inward rectifier potassium channels. Cloning, expression and structure-function studies.
A PCR-based cloning strategy was used to identify novel subunits of the two-transmembrane domain inward rectifier potassium channel family from rat brain, heart, and skeletal muscle. When expressed in Xenopus oocytes, two of these clones (Kir4.1 and Kir2.3) gave rise to inwardly rectifying potassium currents. Two-electrode voltage clamp commands to potentials negative to EK evoked inward potass...
متن کاملFunctional properties of a truncated recombinant GIRK5 potassium channel.
Xenopus laevis oocytes codify a G-protein-activated inward rectifier potassium channel (GIRK5 or Kir3.5). Coinjection of other GIRKs, the muscarinic m2 receptor, or Gbetagamma protein cRNAs is required to observe functional GIRKx-GIRK5 heteromultimers in oocytes. Studies with GIRK2 isoforms have shown that the size of the amino or carboxyl terminus plays a crucial role on giving functional K(+)...
متن کاملA recombinant inwardly rectifying potassium channel coupled to GTP- binding proteins
GTP-binding (G) proteins have been shown to mediate activation of inwardly rectifying potassium (K+) channels in cardiac, neuronal and neuroendocrine cells. Here, we report functional expression of a recombinant inwardly rectifying channel which we call KGP (or hpKir3.4), to signify that it is K+ selective, G-protein-gated and isolated from human pancreas. KGP expression in Xenopus oocytes resu...
متن کاملAsymmetrical contributions of subunit pore regions to ion selectivity in an inward rectifier K+ channel.
We have investigated aspects of ion selectivity in K+ channels by functional expression of wild-type and mutant heteromultimeric G protein-coupled inward-rectifier K+ (GIRK) channels in Xenopus oocytes. Within the K+ channel pore (P) region signature sequence, a large number of point mutations in GIRK1 and GIRK4 subunits have been made at a key tyrosine residue--the "signature" tyrosine of the ...
متن کاملIdentification of domains conferring G protein regulation on inward rectifier potassium channels
Cardiac m2 muscarinic acetylcholine receptors reduce heart rate by coupling to heterotrimeric (alpha beta gamma) guanine nucleotide-binding (G) proteins that activate IKACh, an inward rectifier K+ channel (IRK). Activation of the GIRK subunit of IKACh requires G beta gamma subunits; however, the structural basis of channel regulation is unknown. To determine which sequences confer G beta gamma ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- FEBS letters
دوره 348 3 شماره
صفحات -
تاریخ انتشار 1994