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XB-ART-19478
Proc Natl Acad Sci U S A July 18, 1995; 92 (15): 6758-62.

Inhibition of function in Xenopus oocytes of the inwardly rectifying G-protein-activated atrial K channel (GIRK1) by overexpression of a membrane-attached form of the C-terminal tail.

Dascal N , Doupnik CA , Ivanina T , Bausch S , Wang W , Lin C , Garvey J , Chavkin C , Lester HA , Davidson N .


Abstract
Coexpression in Xenopus oocytes of the inwardly rectifying guanine nucleotide binding (G)-protein-gated K channel GIRK1 with a myristoylated modification of the (putative) cytosolic C-terminal tail [GIRK1 aa 183-501 fused in-frame to aa 1-15 of p60src and denoted src+ (183-501)] leads to a high degree of inhibition of the inward G-protein-gated K+ current. The nonmyristoylated segment, src- (183-501), is not active. Although some interference with assembly is not precluded, the evidence indicates that the main mechanism of inhibition is interference with functional activation of the channel by G proteins. In part, the tail functions as a blocking particle similar to a "Shaker ball"; it may also function by competing for the available supply of free G beta gamma liberated by hormone activation of a seven-helix receptor. The non-G-protein-gated weak inward rectifier ROMK1 is less effectively inhibited, and a Shaker K channel was not inhibited. Immunological assays show the presence of a high concentration of src+ (183-501) in the plasma membrane and the absence of any membrane forms for the nonmyristoylated segment.

PubMed ID: 7542774
PMC ID: PMC41408
Article link: Proc Natl Acad Sci U S A


Species referenced: Xenopus
Genes referenced: kcnj1 kcnj3

References [+] :
Babila, Assembly of mammalian voltage-gated potassium channels: evidence for an important role of the first transmembrane segment. 1994, Pubmed, Xenbase