Shaker K+ channels

Time constants and mean single-channel open times of Shaker K. channel splice variants... 

Fig. 4. Schematic organization of the Shaker K channel gene. The coordinates of the physical map are as in [9]. The direction of transcription is indicated by arrows. Approximate location of exons is given by boxes. Open box corresponds to noncoding exons, lettered boxes to alternative amino-terminal ends of Shaker channel proteins and the core region, respectively, numbered boxes to the two alternative carboxy-terminal ends. Exon numbers are as in [53].

A detailed model of K+ channel inactivation has been derived from mutagenesis experiments on the original Shaker K+ channels from Drosophila [36, 37]. The N-ter-minal of the K+ channel serves as an inactivation particle... 

Cyclic nucleotide-modulated ion channels (Table 6-2) are not K+-selective. Nevertheless, their inward current of Na+ and Ca2+ ions is conducted through a channel that is similar in overall architecture to Shaker K+ channels. This protein family includes the CNG channels, which respond only to cyclic nucleotides, and the HCN channels, which are activated synergistically by hyperpolarization and cyclic nucleotide binding [38,40]. The CNG channels are involved in signaling of visual and olfactory information and serve as cyclic nucleotide-gated Ca2+ channels. In contrast, the HCN channels are required for normal rhythmic electrical discharges by the sinoatrial node in the heart and the pacemaker cells of the thalamus. 

Kelley WP, Wolters AM, Sacks JT, Jockusch RA, Jurchen JC, Williams ER, Sweedler JV, Gilly WF (2003) Characterization of a Novel Gastropod Toxin (6-Bromo-2-mercaptotrypt-amine) That Inhibits Shaker K Channel Activity. J Biol Chem 278 34934... 

Fig. 1. (A) Recordings of ionic currents and gating currents of Shaker K channel...

Fig. 3. Summary of the results of histidine scanning in Shaker K channel. When replaced by histidine, the first four basic residues (R362 through R371) translocate completely from intracellular to extracellular while the next two residues (K374 and R377) are not titratable.

One of these probes was modified so as to have a cysteine reactive site, and at the same time it was made less hydrophobic to decrease its partition in the lipid bilayer with the idea of inserting the probe in predetermined sites of a channel. For this purpose the Shaker K channel... 

Fig. 4. (A) Measured distances using LRET in the Shaker K channel. Tb represents...

Baker, O. S., Larsson, H. P., Mannuzzu, L. M., and Isacoff, E. Y (1998). Three transmembrane conformation and sequence-dependent displacement of the S4 domain in Shaker K+ channel gating. Neuron 20, 1283-1294. 

Cha, A., and Bezanilla, F. (1997). Characterizing voltage-dependent conformational changes in the Shaker K+ channel with fluorescence. Neuron 19, 1127-1140. 

Perozo, E., MacKinnon, R., Bezanilla, F., and Stefani, E. (1993). Gating currents from a non-conducting mutant reveal open-closed conformations in Shaker K+ channels. Neuron 11, 353-358. 

Starace, D., and Bezanilla, F. (1999). Histidine at position 362 causes inwardly rectifying H+ conduction in Shaker K+ channel. Biophys.J. 76, A266. 

Thompson, J. and Begenisich, T., External TEA block of shaker K+ channels is coupled to the movement of K+ ions within the selectivity filter. /. Gen. Physiol. 122, 239-246 (2003). 

MacKinnon R, Reinhart PH, White MN (1988) Charybdotoxin block of Shaker K+ channels suggests that different types of K+channels share common features. Neuron 1 997-1001... 

HERG trapping of MK-499, despite its large size, suggests that the vestibule of the HERG channel is larger than the well-studied Shaker K+ channel. Indeed,... 

The first voltage-gated potassium channel to be identified was the gene encoding the Shaker mutation in the fruit fly Drosophila. Figure 9.3 presents the hrst pictures of the tetrameric Shaker K+ channel with... 

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