The ATP-sensitive K(+)-channel (K(ATP)) controls early left-right patterning in Xenopus and chick embryos.

Consistent left-right asymmetry requires specific ion currents. We characterize a novel laterality determinant in Xenopus laevis: the ATP-sensitive K(+)-channel (K(ATP)). Expression of specific dominant-negative mutants of the Xenopus Kir6.

Polyamine permeation and rectification of Kir4.1 channels.

Inward rectifier K(+) (Kir) channels are expressed in multiple neuronal and glial cells. Recent studies have equated certain properties of exogenously expressed Kir4.1 channels with those of native K(+) currents in brain cells, as well as demonstrating the expression of Kir4.

Human FXYD2 G41R mutation responsible for renal hypomagnesemia behaves as an inward-rectifying cation channel.

A mutation in the human FXYD2 polypeptide (Na-K-ATPase gamma subunit) that changes a conserved transmembrane glycine to arginine is linked to dominant renal hypomagnesemia. Xenopus laevis oocytes injected with wild-type FXYD2 or the mutant G41R cRNAs expressed large nonselective ion currents. However, in contrast to the wild-type FXYD2 currents, inward rectifying cation currents were induced by hyperpolarization pulses in oocytes expressing the G41R mutant.

Complex rectification of Müller cell Kir currents.

Although Kir4.1 channels are the major inwardly rectifying channels in glial cells and are widely accepted to support K+- and glutamate-uptake in the nervous system, the properties of Kir4.1 channels during vital changes of K+ and polyamines remain poorly understood.

C-terminal determinants of Kir4.2 channel expression.

Inward rectifier potassium (Kir) channels serve important functional and modulatory roles in a wide variety of cells. While the activity of several members of this channel family are tightly regulated by intracellular messengers such as adenosine triphosphate, G proteins, protein kinases and pH, other members are tonically active and activity is controlled only by the expression level of the protein. In a number of Kir channels, sequence motifs have been identified which determine how effectively the channel is trafficked to and from the plasma membrane.