Accessory subunits

We have found that the communication between Ca2+ sparks and BK channels can be tuned by membrane potential (this study, Herrera et al 2001) and by the accessory / subunit (Brenner et al 2000, Petkov et al 2001). This effect can be accounted for based on the allosteric relationship between the BK channel voltage and Ca2+ sensors, whereby membrane potential depolarization favours a channel conformation that has a higher Ca2+ sensitivity. The /b subunit has a similar role to increase the apparent Ca2+ sensitivity of the a subunit. 

Pourrier, M Schram, G. and Nattel, S. (2003) Properties, expression and potential roles of cardiac K+ channel accessory subunits MinK, MiRPs, KChIP, and KChAP. The Journal of Membrane Biology, 194, 141-152. 

Fan L, Sanschagrin PC, Kaguni LS, Kuhn LA. The accessory subunit of mtDNA polymerase shares structural homology with aminoacyl-tRNA synthetases implications for a dual role as a primer recognition factor and processivity clamp. Proc. Natl. Acad. Sci. U.S.A. 1999 96 9527-9532. 

IF bod.- Can you use your cysteine-modifying reagents to map the sites of interaction of accessory subunits ... 

In 2001, using cryo-electron microscopy and single particle analysis, Sato and colleagues provided the first three-dimensional view of the Nay channel isolated from the eel Electrophorus electricus. The channel was found to have a bell-shaped extracellular surface structure with square-shaped intracellular base and a spherical top (Figure 16.10). In addition to the pore-forming a-subunits, the Nay channels have four additional accessory subunits (Naypi,-Nayp4), each measuring... 

Name Human Gene Human Chromosome Accessory Subunits... 

Name Human Gene Human Chromosome Accessory Subunits Tissue Distribution Inhibitors (Antagonists) Activators (T jonists)... 

The ion-channel accessory subunits are also the targets of various compounds, indicating their importance to the pharmaceutical industry. The smooth muscle-specific (3-1 subunit of the Kcal-1 (BK.) channel has profound effects in regulating vascular smooth muscle tone, and thus blood pressure, as well as urinary bladder (where it is most heavily expressed) contractility. Targeting the Kcal-1 channel (3-1 subunit may lead to novel therapeutics to control blood pressure and urinary incontinence. The Kcal-1 channel has a... 

Tian C, Vanoye CG, Kang C, Welch RC, Kim HJ, George AL, Sanders CR (2007) Preparation, functional characterization, and NMR studies of human KCNEl, a voltage-gated potassium channel accessory subunit associated with deafness and long QT syndrome. Biochemistry 46 11459-11472... 

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