Journal article
Sh and Eag K + Channel Subunit Interaction in Frog Oocytes Depends on Level and Time of Expression
Biophysical journal, Vol.79(3), pp.1358-1368
2000
DOI: 10.1016/S0006-3495(00)76388-0
PMCID: PMC1301030
PMID: 10968998
Abstract
Subcellular clustering of ion channels critically affects neuronal function. Coexpression of Eag and Sh channel subunits in
Xenopus oocytes leads to accelerated decay of the Sh-like transient K
+ current (Chen, M.-L., T. Hoshi, and C.-F. Wu. 1996.
Neuron. 17:535–542). We report that such interaction depends critically on functional expression level (controlled by RNA injection quantities and indicated by current amplitudes) and developmental time after RNA injection. The accelerated decay became apparent 3 days after coinjection and increased thereafter. This was observed in different ionic conditions and at different voltage steps. However, decay was not accelerated at low expression levels, either within 1–2 days after injection or with reduced amounts of RNA. With sequential RNA injection, preformation of either Eag or Sh channels prevented interactions with the other subunit. The carboxyl terminus of Eag was found to be involved in accelerating, and in retarding recovery from, N-type inactivation. The interaction was reduced upon patch excision in macropatch measurements, suggesting involvement of cytosolic factors. We have reproduced the absence of interaction between Eag and Sh reported previously within 2 days after RNA injection and with low levels of current expression (Tang, C.-Y., C. T. Schulteis, R. M. Jiménez, and D. M. Papazian. 1998.
Biophys. J. 75:1263–1270). Our findings demonstrate that heterologous expression of channels in
Xenopus oocytes is a dynamic process influenced by cell physiology and development. These factors must be considered in interpreting the functional properties of heterologously expressed channels.
Details
- Title: Subtitle
- Sh and Eag K + Channel Subunit Interaction in Frog Oocytes Depends on Level and Time of Expression
- Creators
- Mai-Lei Chen - Department of Biological Sciences, The University of Iowa, Iowa City, Iowa 52242 USAToshinori Hoshi - Department of Physiology and Biophysics, The University of Iowa, Iowa City, Iowa 52242 USAChun-Fang Wu - Department of Biological Sciences, The University of Iowa, Iowa City, Iowa 52242 USA
- Resource Type
- Journal article
- Publication Details
- Biophysical journal, Vol.79(3), pp.1358-1368
- Publisher
- Elsevier Inc
- DOI
- 10.1016/S0006-3495(00)76388-0
- PMID
- 10968998
- PMCID
- PMC1301030
- ISSN
- 0006-3495
- eISSN
- 1542-0086
- Language
- English
- Date published
- 2000
- Academic Unit
- Iowa Neuroscience Institute; Biology
- Record Identifier
- 9984070871402771
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