Agonist-Induced Ca Signaling in HEK-293-Derived Cells Expressing a Single IP Receptor Isoform.

In mammals, three genes encode IP receptors (IPRs), which are involved in agonist-induced Ca signaling in cells of apparently all types. Using the CRISPR/Cas9 approach for disruption of two out of three IPR genes in HEK-293 cells, we generated three monoclonal cell lines, IP3R1-HEK, IP3R2-HEK, and IP3R3-HEK, with the single functional isoform, IPR1, IPR2, and IPR3, respectively. All engineered cells responded to ACh with Ca transients in an "all-or-nothing" manner, suggesting that each IPR isotype was capable of mediating CICR.

Proliferation, migration, and resistance to oxidative and thermal stresses of HT1080 cells with knocked out genes encoding Hsp90α and Hsp90β.

Heat shock protein 90 (Hsp90) fulfils essential housekeeping functions in the cell associated with the folding, stabilization, and turnover of various proteins. In mammals, there exist two Hsp90 isoforms, stress-inducible Hsp90α and constitutively expressed Hsp90β. In an attempt to identify cellular processes dependent on Hsp90α and Hsp90β, we generated a panel of clones of human fibrosarcoma HT1080 cells with the knocked out HSP90AA1 or HSP90AB1 genes encoding, respectively, Hsp90α and Hsp90β.

Contribution of TRPC3-mediated Ca entry to taste transduction.

The current concept of taste transduction implicates the TASR/PLCβ2/IPR3/TRPM5 axis in mediating chemo-electrical coupling in taste cells of the type II. While generation of IP has been verified as an obligatory step, DAG appears to be a byproduct of PIP cleavage by PLCβ2. Here, we provide evidence that DAG-signaling could play a significant and not yet recognized role in taste transduction.

Taste Cells of the Type III Employ CASR to Maintain Steady Serotonin Exocytosis at Variable Ca in the Extracellular Medium.

Type III taste cells are the only taste bud cells which express voltage-gated (VG) Ca channels and employ Ca-dependent exocytosis to release neurotransmitters, particularly serotonin. The taste bud is a tightly packed cell population, wherein extracellular Ca is expected to fluctuate markedly due to the electrical activity of taste cells. It is currently unclear whether the Ca entry-driven synapse in type III cells could be reliable enough at unsteady extracellular Ca.

Modeling of Ca transients initiated by GPCR agonists in mesenchymal stromal cells.

The integrative study that included experimentation and mathematical modeling was carried out to analyze dynamic aspects of transient Ca signaling induced by brief pulses of GPCR agonists in mesenchymal stromal cells from the human adipose tissue (AD-MSCs). The experimental findings argued for IP/Ca-regulated Ca release via IP receptors (IPRs) as a key mechanism mediating agonist-dependent Ca transients. The consistent signaling circuit was proposed to formalize coupling of agonist binding to Ca mobilization for mathematical modeling.