NanoTouch: intracellular recording using transmembrane conductive nanoparticles.

Observations of the electrophysiological properties of cells are important for understanding cellular functions and their underlying mechanisms. Short action potentials in axons are essential to rapidly deliver signals from the neuronal cell body to the terminals, whereas longer action potentials are required for sufficient calcium influx for transmitter release at the synaptic terminals and for cardiomyocyte and smooth muscle contractions. To accurately observe the shape and timing of depolarizations, it is essential to measure changes in the intracellular membrane potential.

Luminal chloride-dependent activation of endosome calcium channels: patch clamp study of enlarged endosomes.

Although Ca(2+) release from early endosomes (EE) is important for the fusion of primary endosomes, the presence of an ion channel responsible for releasing calcium from the EE has not been shown. A recent proteomics study has identified the TRPV2 channel protein in EE, suggesting that transient receptor potential-like Ca(2+) channels may be in endosomes. The submicron size of endosomes has made it difficult to study their ion channels in the past.

Otopetrin 1 activation by purinergic nucleotides regulates intracellular calcium.

Otopetrin1 (Otop1) is a multitransmembrane domain protein required for the formation of otoconia in the vertebrate inner ear. Otoconia are complex calcium carbonate (CaCO(3)) biominerals that are required for the sensation of gravity. Examination of the phenotypes of animals with mutations or deficiencies in Otop1 suggests a direct role for Otop1 in the initiation of extracellular biomineralization, possibly through the regulation of intracellular Ca(2+).

Wolframin expression induces novel ion channel activity in endoplasmic reticulum membranes and increases intracellular calcium.

Wolfram syndrome is an autosomal recessive neuro-degenerative disorder associated with juvenile onset non-autoimmune diabetes mellitus and progressive optic atrophy. The disease has been attributed to mutations in the WFS1 gene, which codes for a protein predicted to possess 9-10 transmembrane segments. Little is known concerning the function of the WFS1 protein (wolframin).

SCMTR: a chloride-selective, membrane-anchored peptide channel that exhibits voltage gating.

The design, synthesis, and characterization of a synthetic chloride membrane transporter, SCMTR (synthetic chloride membrane transporter, "scimitar"), are presented. The compound [CH3(CH2)17]2NCOCH2OCH2CO-GGGPGGG-OBzl inserts rapidly into liposomes and planar lipid bilayers. SCMTR has a 1.