Abstract

A transient K+ current coded by the Shaker gene was identified in muscle and expressed in Xenopus oocytes by injecting cRNA transcribed from a cloned cDNA. The Shaker current has not previously been identified in neurons. Mutational analysis now reveals that in neurons, Shaker is required for expression of a very rapidly inactivating K+ current with a depolarized steady-state inactivation curve. Together, these properties distinguish the Shaker-coded current from similar fast transient K+ currents coded by other genes. The Sh5 mutation further enhanced the depolarization of the Shaker current steady-state inactivation curve. Deletion of the Shaker gene completely removes the transient K+ current from a small percentage of neurons (15%) in a mixed population, and removes a portion of the whole-cell current in about 35% of neurons. The remaining 50% of neurons were apparently unaffected by deletion of the Shaker gene. The unique combination of rapid inactivation and depolarized steady-state inactivation of the Shaker current may reflect a unique functional role for this curent in the nervous system such as the rapid repolarization of action potentials.

Original languageEnglish
Pages (from-to)129-140
Number of pages12
JournalNeuron
Volume4
Issue number1
DOIs
StatePublished - Jan 1990

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