Fusion-activated Ca2+ entry via vesicular P2X4 receptors promotes fusion pore opening and exocytotic content release in pneumocytes.

ABSTRACT: Ca(2+) is considered a key element in multiple steps during regulated exocytosis. During the postfusion phase, an elevated cytoplasmic Ca(2+) concentration ([Ca(2+)])(c) leads to fusion pore dilation. In neurons and neuroendocrine cells, this results from activation of voltage-gated Ca(2+) channels in the plasma membrane. However, these channels are activated in the prefusion stage, and little is known about Ca(2+) entry mechanisms during the postfusion stage. This may be particularly important for slow and nonexcitable secretory cells. We recently described a "fusion-activated" Ca(2+) entry (FACE) mechanism in alveolar type II (ATII) epithelial cells. FACE follows initial fusion pore opening with a delay of 200-500 ms. The site, molecular mechanisms, and functions of this mechanism remain

SUBMITTER: Miklavc P 

PROVIDER: S-EPMC3167537 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature