Control of Insulin Release by Transient Receptor Potential Melastatin 3 (TRPM3) Ion Channels.

Background/aims: The release of insulin in response to increased levels of glucose in the blood strongly depends on Ca influx into pancreatic beta cells by the opening of voltage-gated Ca channels. Transient Receptor Potential Melastatin 3 proteins build Ca permeable, non-selective cation channels serving as pain sensors of noxious heat in the peripheral nervous system. TRPM3 channels are also strongly expressed in pancreatic beta cells that respond to the TRPM3 agonist pregnenolone sulfate with Ca influx and increased insulin release.

Pharmacological properties of TRPM3 isoforms are determined by the length of the pore loop.

Background And Purpose: Transient receptor potential melastatin 3 (TRPM3) is a non-selective cation channel that plays a pivotal role in the peripheral nervous system as a transducer of painful heat signals. Alternative splicing gives rise to several TRPM3 variants. The functional consequences of these splice isoforms are poorly understood.

Protein Kinase CK2 Controls Ca2.1-Dependent Calcium Currents and Insulin Release in Pancreatic β-Cells.

The regulation of insulin biosynthesis and secretion in pancreatic β-cells is essential for glucose homeostasis in humans. Previous findings point to the highly conserved, ubiquitously expressed serine/threonine kinase CK2 as having a negative regulatory impact on this regulation. In the cell culture model of rat pancreatic β-cells INS-1, insulin secretion is enhanced after CK2 inhibition.

Transient receptor potential A1 channels regulate epithelial cell barriers formed by MDCK cells.

Transient receptor potential A1 channels are well-known as chemosensors in neuronal cells. However, recent studies also point to non-neuronal functions in epithelia. Here, we show that TRPA1 channels are expressed in epithelial MDCK II cells and contribute to Ca(2+) influx and whole-cell currents after stimulation with AITC.

TRPC5 is a Ca2+-activated channel functionally coupled to Ca2+-selective ion channels.

TRPC5 forms non-selective cation channels. Here we studied the role of internal Ca(2+) in the activation of murine TRPC5 heterologously expressed in human embryonic kidney cells. Cell dialysis with various Ca(2+) concentrations (Ca(2+)(i)) revealed a dose-dependent activation of TRPC5 channels by internal Ca(2+) with EC(50) of 635.

ONO-54918-07, a stable prostacyclin analogue, mimics the effect of prostaglandin PGE1 on NG108-15 cells.

The aim of this study was to explore the effect of 0NO-54918-07, a stable prostacyclin analogue, on the current-voltage (IV) curve and the intracellular Ca2+ concentration [Ca2+]i of NG108-15 neuroblastoma x glioma hybrid cells. The IV curve was measured with ramp pulses from -70 to 0 mV, and [Ca2+]i was determined with Fura 2. Bath application of 0.

Primary structure, chromosomal localization and expression in immune cells of the murine ORAI and STIM genes.

Recently ORAI and STIM proteins were identified as components of the CRAC channel and the endoplasmic reticulum Ca(2+) sensor, respectively. The ORAI proteins share a predicted structure that includes four transmembrane domains with intracellular N- and C-termini. They share structural similarity with proteins of the tetraspanin superfamily which includes the gamma subunits of voltage-activated Ca(2+) channels (CaVgamma), the transmembrane AMPA regulatory proteins (TARPs), the claudins and the tumor-associated membrane proteins (TMPs).

Murine ORAI2 splice variants form functional Ca2+ release-activated Ca2+ (CRAC) channels.

The stimulation of membrane receptors coupled to the phopholipase C pathway leads to activation of the Ca(2+) release-activated Ca(2+) (CRAC) channels. Recent evidence indicates that ORAI1 is an essential pore subunit of CRAC channels. STIM1 is additionally required for CRAC channel activation.