Differential Effects of Gq Protein-Coupled Uridine Receptor Stimulation on IL-8 Production in 1321N1 Human Astrocytoma Cells.

G-protein-coupled receptors (GPCRs) trigger various physiological functions. GPCR-mediated effects largely depend on the receptor-associated G-protein subtypes. However, compelling evidence suggests that single receptor proteins activate multiple G-protein subtypes to induce diverse physiological responses.

Vesicular nucleotide transporter is involved in ATP storage of secretory lysosomes in astrocytes.

Recent studies have suggested that astrocytes release gliotransmitters (i.e., ATP, L-glutamate, D-serine, and peptide hormones) and participate actively in synaptic functioning.

Duration of fusion pore opening and the amount of hormone released are regulated by myosin II during kiss-and-run exocytosis.

Since the fusion pore of the secretory vesicle is resealed before complete dilation during 'kiss-and-run' exocytosis, their cargoes are not completely released. Although the transient fusion pore is kept open for several seconds, the precise mechanisms that control fusion pore maintenance, and their physiological significance, are not well understood. Using dual-colour TIRF (total internal reflection fluorescence) microscopy in neuroendocrine PC12 cells, we show that myosin II regulates the fusion pore dynamics during kiss-and-run exocytosis.

Role of the polybasic sequence in the Doc2alpha C2B domain in dense-core vesicle exocytosis in PC12 cells.

The double C2 (Doc2) family is characterized by an N-terminal Munc13-1-interacting domain and C-terminal tandem C2 domains, and it comprises three isoforms, Doc2alpha, Doc2beta, and Doc2gamma, in humans and mice. Doc2alpha, the best-characterized, brain-specific isoform, exhibits Ca(2+)-dependent phospholipid-binding activity through its C2A domain, and the Ca(2+)-binding activity is thought to be important for the regulation of Ca(2+)-dependent exocytosis. In contrast to the C2A domain, however, nothing is known about the physiological functions of the C2B domain in regulated exocytosis.