摘要
α-latrotoxin (α-LTX), a neurotoxin from black-widow spider, causes vesicles release in pre- synapse of nerve terminal after binding to specific membrane receptors. α-LTXN4C is an effective tool binding to calcium independent receptor for latrotoxin (CIRL), which is used to elucidate the mechanism of receptor-mediated signal pathway. In our study on the pancreatic β cells, we found that α-LTX inserts into the plasma membrane and forms stable non-selective cation channels. The influx of ex- tracellular Ca2+ through the channels causes massive Ca2+-dependent exocytosis of insulin-containing vesicles, whereas, α-LTXN4C, binding with its receptor CIRL in extracellular divalent cation-dependent way, increases [Ca2+]i by mobilization of the intracellular calcium stores.
α-latrotoxin （α-LTX）, a neurotoxin from black-widow spider, causes vesicles release in presynapse of nerve terminal after binding to specific membrane receptors, α-LTX^N4C is an effective tool binding to calcium independent receptor for latrotoxin （CIRL）, which is used to elucidate the mechanism of receptor-mediated signal pathway. In our study on the pancreatic β cells, we found that α-LTX inserts into the plasma membrane and forms stable non-selective cation channels. The influx of extracellular Ca^2＋ through the channels causes massive Ca^2＋-dependent exocytosis of insulin-containing vesicles, whereas, α-LTX^N4C, binding with its receptor CIRL in extracellular divalent cation-dependent way, increases [Ca^2＋]i by mobilization of the intracellular calcium stores.
基金
We thank Prof.Yuri Ushkaryov for supplying α-LTXN4C.This work was supported by the National Natural Science Foundation of China(Grant Nos.30270363&30130230)
the National Basic Research Program of China(Grant Nos.G1999054000&2004CB720000).
