SNAP-25 palmitoylation and plasma membrane targeting require a functional secretory pathway
SNAP-25 palmitoylation and plasma membrane targeting require a functional secretory pathway
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DOI：
10.1091/mbc.9.3.585
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发表时间：
1998-03-01
影响因子：
3.3
通讯作者：
Linder, ME
中科院分区：
文献类型：
--
作者：
Gonzalo, S;Linder, ME
突触体相关蛋白25 kDa（SNAP-25）是一种棕榈酰化的膜蛋白，对突触末梢释放神经递质至关重要。我们使用神经元细胞系来研究SNAP-25的生物合成和翻译后加工，以研究棕榈酰化如何有助于蛋白质的亚细胞定位。SNAP-25作为可溶性蛋白质合成，其在合成后约20分钟经历棕榈酰化。蛋白质的棕榈酰化与其稳定的膜缔合相一致。用布雷菲德菌素A或其他运输干扰物处理细胞抑制新合成的SNAP-25的棕榈酰化，并废除膜缔合。这些结果表明，SNAP-25的加工及其靶向质膜依赖于完整的转运机制沿着胞外途径。SNAP-25棕榈酰化和膜缔合的动力学以及这些参数对布雷菲德菌素A的敏感性表明了将蛋白质靶向质膜的新的运输途径。在体外，SNAP-25稳定地与膜结合，在化学脱酰后不从膜释放。我们建议，棕榈酰化的SNAP-25所需的初始膜靶向的蛋白质，但其他相互作用可以保持膜协会在脂肪酰化的情况下。
Synaptosomal-associated protein of 25 kDa (SNAP-25) is a palmitoylated membrane protein essential for neurotransmitter release from synaptic terminals. We used neuronal cell lines to study the biosynthesis and posttranslational processing of SNAP-25 to investigate how palmitoylation contributes to the subcellular localization of the protein. SNAP-25 was synthesized as a soluble protein that underwent palmitoylation approximately 20 min after synthesis. Palmitoylation of the protein coincided with its stable membrane association. Treatment of cells with brefeldin A or other disrupters of transport inhibited palmitoylation of newly synthesized SNAP-25 and abolished membrane association. These results demonstrate that the processing of SNAP-25 and its targeting to the plasma membrane depend on an intact transport mechanism along the exocytic pathway. The kinetics of SNAP-25 palmitoylation and membrane association and the sensitivity of these parameters to brefeldin A suggest a novel trafficking pathway for targeting proteins to the plasma membrane. In vitro, SNAP-25 stably associated with membranes was not released from the membrane after chemical deacylation. We propose that palmitoylation of SNAP-25 is required for initial membrane targeting of the protein but that other interactions can maintain membrane association in the absence of fatty acylation.