Carboxy-terminal domain mediates assembly of the voltage-gated rat ether-à-go-go potassium channel.
The specific assembly of subunits to oligomers is an important prerequisite for producing functional potassium channels. We have studied the assembly of voltage-gated rat ether-à-go-go (r-eag) potassium channels with two complementary assays. In protein overlay binding experiments it was shown that a 41-amino-acid domain, close to the r-eag subunit carboxy-terminus, is important for r-eag subunit interaction. In an in vitro expression system it was demonstrated that r-eag subunits lacking this assembly domain cannot form functional potassium channels. Also, a approximately 10-fold molar excess of the r-eag carboxy-terminus inhibited in co-expression experiments the formation of functional r-eag channels. When the r-eag carboxy-terminal assembly domain had been mutated, the dominant-negative effect of the r-eag carboxy-terminus on r-eag channel expression was abolished. The results demonstrate that a carboxy-terminal assembly domain is essential for functional r-eag potassium channel expression, in contrast to the one of Shaker-related potassium channels, which is directed by an amino-terminal assembly domain.
Ludwig
J
J
Zentrum für Molekulare Neurobiologie, Universität Hamburg, Germany.
Owen
D
D
Pongs
O
O
D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D051638:Ether-A-Go-Go Potassium Channels; D017136:Ion Transport; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D011487:Protein Conformation; D017510:Protein Folding; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D051637:Shaker Superfamily of Potassium Channels
D051638:Ether-A-Go-Go Potassium Channels; D015221:Potassium Channels; D012333:RNA, Messenger; D051637:Shaker Superfamily of Potassium Channels; D011188:Potassium