Newest Articles
Energetics of cosubstrate binding to MelBThe melibiose symporter MelB couples melibiose transport to that of cations such as Na+. Hariharan and Guan show that the binding of Na+ and melibiose is thermodynamically cooperative and that Na+ coupling is based on ion concentrations and competitive binding, but not ion selectivity.
Na/K pump mutations that induce hyperaldosteronismMutated Na/K pumps in adrenal adenomas are thought to cause hyperaldosteronism via a gain-of-function effect involving a depolarizing inward current. The findings of Meyer et al. suggest instead that the common mechanism by which Na/K pump mutants lead to hyperaldosteronism is a loss-of-function.
Voltage sensing in mammalian EC couplingIn excitation–contraction coupling, voltage-sensing modules (VSMs) of CaV1.1 Ca2+ channels simultaneously gate the associated pore and Ca2+ release channels in the sarcoplasmic reticulum. Ferreira Gregorio et al. find that VSMs adopt two inactivated states, and the degree of inactivation is dependent on external Ca2+ and the mouse strain used.
Age-associated pacemaker function deteriorationPacemaker function deteriorates in advanced age. Behar and Yaniv show that both intracellular and membrane mechanisms are responsible for age-associated pacemaker function deterioration and explain why the maximal beating rate is restored as a result of changes in sensitivity of HCN4 to cAMP and phospholamban to PKA.
Coarse-grained simulations of Phe-Gly nucleoporinsThe phenylalanine-glycine–repeat nucleoporins are essential for transport through the nuclear pore complex. Pulupa et al. observe reptation of these nucleoporins on a physiological timescale in coarse-grained computational simulations.
Slow fusion pore creates a unique reaction chamberA lumenal secretory granule protein can slow fusion pore dilation and thus its own discharge. Bohannon et al. demonstrate another outcome: the creation of a nanoscale chemical reaction chamber for granule contents in which the pH is suddenly neutralized upon fusion.
Mechanisms of Na+ channel regulation by β1 and β3Voltage-gated NaV channels are modulated by two different noncovalent accessory subunits: β1 and β3. Zhu et al. present data showing that β1 and β3 cause distinct effects on channel gating because they interact with NaV channels at different locations. β3 regulates the voltage sensor in domain III, whereas β1 regulates the one in domain IV.
Current Issue
October 2, 2017
Volume 149, No. 10
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Reviews & Opinions
- A symporter’s secrets shown
New JGP study explores the thermodynamic cycle and cation preference of the sugar symporter MelB.
- Threading the biophysics of mammalian Slo1 channels onto structures of an invertebrate Slo1 channel
Zhou et al. consider the biophysics of large-conductance Ca2+-activated Slo1 channels in the context of Aplysia Slo1 structures.
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Insufficient sodium-ion extrusion by mutated Na+,K+-ATPases causes hyperaldosteronism.