Methods and Approaches
Channelrhodopsin-2 is the key ion channel in optogenetics. Walther et al. demonstrate that coupling channelrhodopsin-2 to the β1 subunit of voltage-gated sodium channels allows action potentials to be triggered by blue-light illumination of Xenopus laevis oocytes coexpressing different types of sodium channel α subunits.
Voltage-sensing phosphatases (VSPs) can be used to experimentally manipulate cellular phosphoinositide levels. Kawanabe et al. describe an enhanced VSP based on the zebrafish orthologue Dr-VSP and developed by the introduction of a mutation into a membrane-interacting site and fusion with the N-terminal cytoplasmic region of sea squirt VSP.
In several preparations, it has been found that synaptic vesicles can be released either quickly or slowly in response to a strong stimulus. Blanchard et al. differentially modify the proportion of quick versus slow vesicles by prior subthreshold or suprathreshold stimulations.
Mice lacking BK potassium channels have weakness with stimulation of peripheral nerve, but not muscle, which is caused by a defect in neuromuscular transmission. Prolonging the motor neuron action potential fully normalizes in vivo strength.
TRPM2 cation channels are activated by ADP ribose (ADPR), which binds to two distinct locations in the N- and C-terminal cytosolic domains. Tóth et al. selectively determine the ligand-binding affinities of these two binding sites in sea anemone TRPM2 and provide insights into the mechanistic contributions of several amino acids within the N-terminal site.