Diacylglycerol induces fusion of nuclear envelope membrane precursor vesicles
Diacylglycerol induces fusion of nuclear envelope membrane precursor vesicles
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DOI：
10.1074/jbc.m412863200
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发表时间：
2005-12-16
影响因子：
4.8
通讯作者：
Poccia, DL
中科院分区：
文献类型：
--
作者：
Barona, T;Byrne, RD;Poccia, DL
从海胆卵分离的纯化膜囊泡在胞质溶胶的存在下在GTP水解后形成围绕精子核的核膜。这些囊泡（MV 1），高度富集磷脂酰肌醇（PtdIns）的低密度亚组分，需要核膜的形成。MV 1与贡献大部分核膜的第二部分的膜融合可以在没有GTP的情况下通过外源性细菌PtdIns特异性磷脂酶C（PI-PLC）启动，所述磷脂酶C水解PtdIns以形成二酰基甘油酯和肌醇1-磷酸。这PI-PLC水解海胆膜囊泡PtdIns的一个子集，甘油二酯富含长链，多不饱和物种揭示了一种新的液相色谱-质谱分析。富含PtdIns的大单层囊泡（LUVs）可以替代MV 1参与PI-PLC诱导的核膜形成。此外，MV 1用PI-PLC预水解并洗涤以除去肌醇，导致在没有进一步PI-PLC处理的情况下与MV 2自发形成核膜。富含二酰基甘油的LUV模拟预水解的MV 1。这些结果表明，生产膜不稳定甘油二酯在膜中富含PtdIns可能有利于膜融合在一个自然的膜系统，并建议MV 1，它只结合到两个地方的精子核，可能会启动融合局部。
Purified membrane vesicles isolated from sea urchin eggs form nuclear envelopes around sperm nuclei following GTP hydrolysis in the presence of cytosol. A low density subfraction of these vesicles (MV1), highly enriched in phosphatidylinositol ( PtdIns), is required for nuclear envelope formation. Membrane fusion of MV1 with a second fraction that contributes most of the nuclear envelope can be initiated without GTP by an exogenous bacterial PtdIns-specific phospholipase C (PI-PLC) which hydrolyzes PtdIns to form diacyl-glycerides and inositol 1-phosphate. This PI-PLC hydrolyzes a subset of sea urchin membrane vesicle PtdIns into diglycerides enriched in long chain, polyunsaturated species as revealed by a novel liquid chromatography-mass spectrometry analysis. Large unilammelar vesicles (LUVs) enriched in PtdIns can substitute for MV1 in PI-PLC induced nuclear envelope formation. Moreover, MV1 prehydrolyzed with PI-PLC and washed to remove inositols leads to spontaneous nuclear envelope formation with MV2 without further PI-PLC treatment. LUVs enriched in diacylglycerol mimic prehydrolyzed MV1. These results indicate that production of membrane-destabilizing diglycerides in membranes enriched in PtdIns may facilitate membrane fusion in a natural membrane system and suggest that MV1, which binds only to two places on the sperm nucleus, may initiate fusion locally.