Referenced in: none

Automatically associated channels: Slo1

Title: Voltage-dependent calcium channels at the plasma membrane, but not vesicular channels, couple exocytosis to endocytosis.

Authors: Lei Xue, Zhen Zhang, Benjamin D McNeil, Fujun Luo, Xin-Sheng Wu, Jiansong Sheng, Wonchul Shin, Ling-Gang Wu

Journal, date & volume: Cell Rep, 2012 Jun 28 , 1, 632-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22813738

Abstract
Although calcium influx triggers endocytosis at many synapses and non-neuronal secretory cells, the identity of the calcium channel is unclear. The plasma membrane voltage-dependent calcium channel (VDCC) is a candidate, and it was recently proposed that exocytosis transiently inserts vesicular calcium channels at the plasma membrane, thus triggering endocytosis and coupling it to exocytosis, a mechanism suggested to be conserved from sea urchin to human. Here, we report that the vesicular membrane, when inserted into the plasma membrane upon exocytosis, does not generate a calcium current or calcium increase at a mammalian nerve terminal. Instead, VDCCs at the plasma membrane, including the P/Q-type, provide the calcium influx to trigger rapid and slow endocytosis and, thus, couple endocytosis to exocytosis. These findings call for reconsideration of the vesicular calcium channel hypothesis. They are likely to apply to many synapses and non-neuronal cells in which VDCCs control exocytosis, and exocytosis is coupled to endocytosis.