Membrane binding of a single M domain is sufficient to fully activate the enzymatic activity of the CCT dimer while sustaining the low affinity, reversible membrane interaction required for regulation of CCT activity.”
“Calcium- and voltage-activated potassium channels (BK) are regulated by a multiplicity of signals. The prevailing view is that different BK gating mechanisms converge to determine channel opening and that these gating
mechanisms are allosterically coupled. In most instances the pore forming alpha subunit of BK is associated with one of four alternative beta subunits that appear to target specific gating mechanisms to regulate the channel activity. In particular, Sotrastaurin in vivo beta 1 stabilizes the active configuration of the
BK voltage sensor having a large effect on BK Ca2+ sensitivity. To determine the extent to which beta subunits regulate the BK voltage sensor, we measured gating currents induced by the pore-forming BK alpha subunit alone and with the different beta subunits expressed in Xenopus oocytes (beta 1, beta 2IR, beta 3b, and beta 4). We found that beta 1, beta 2, and beta 4 stabilize the BK voltage sensor in the active conformation. beta 3 has no effect on voltage sensor equilibrium. In addition, beta 4 decreases the apparent number of charges per voltage sensor. selleckchem The decrease in the charge associated with the voltage sensor in alpha beta 4 channels explains most of their biophysical properties. For channels composed of the
alpha subunit alone, gating charge increases slowly with pulse duration as expected if a significant fraction of this charge develops with a time course comparable to that of K+ current activation. In the presence of beta 1, beta 2, and beta 4 this slow component develops in advance of and much more rapidly than ion current activation, suggesting that BK channel opening proceeds in two steps.”
“Estimating survival and documenting causes and timing of mortality events in neonate bighorn sheep (Ovis canadensis) improves understanding of population ecology and factors influencing recruitment. During 2010-2012, we captured and radiocollared 74 neonates in the Black Hills, South Dakota, of which 95% (70) died before 52 weeks of age. Pneumonia (36%) was the leading cause of mortality this website followed by predation (30%). We used known fate analysis in Program MARK to estimate weekly survival rates and investigate the influence of intrinsic variables on 52-week survival. Model S-1 wk,S- 2-8 wks,S- >8 wks had the lowest AIC(c) (Akaike’s Information Criterion corrected for small sample size) value, indicating that age (3-stage age-interval: 1 week, 2-8 weeks, and >8 weeks) best explained survival. Weekly survival estimates for 1 week, 2-8 weeks, and >8 weeks were 0.81 (95% CI = 0.70-0.88), 0.86 (95% CI = 0.81-0.90), and 0.94 (95% CI = 0.91-0.96), respectively. Overall probability of surviving 52 weeks was 0.02 (95% CI = 0.01-0.07).