Similarity in calcium channel activity of annexin V and matrix vesicles in planar lipid bilayers
Similarity in calcium channel activity of annexin V and matrix vesicles in planar lipid bilayers
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DOI：
10.1016/s0006-3495(96)79377-3
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发表时间：
1996-10-01
影响因子：
3.4
通讯作者：
Wuthier, RE
中科院分区：
文献类型：
--
作者：
Arispe, N;Rojas, E;Wuthier, RE
基质囊泡（Matrix vesicles, MVs）是生长骨骼中矿物质形成过程中积累Ca2+的结构，富含膜联蛋白V。当基质囊泡与平面磷脂双层融合时，形成了多导Ca2+通道，其活性与膜联蛋白V通过磷脂酰丝氨酸脂质体传递到双层时所观察到的活性基本相同。通过该通道的Ca2+电流，来自MV或膜联蛋白V脂质体，被Zn2+阻断，正如在合成软骨淋巴中培养的MV吸收Ca2+一样。Zn2+在含有MV或脂质体的一侧阻滞最有效。ATP和GTP差异调节该通道的活性：ATP增加了电流的振幅和电导状态的数量；GTP显著减少了事件和电导状态的数量，导致MV或膜联蛋白V脂质体具有明确的Ca2+通道活性。在ATP、GTP和Zn2+对MV和脂质体系统中Ca2+通道活性的不同影响中，共同的因素是膜联蛋白V的存在。由此我们得出结论，Ca2+进入MV是由于膜联蛋白V在这些膜封闭结构中的存在。
Matrix vesicles (MVs), structures that accumulate Ca2+ during the initiation of mineral formation in growing bone, are rich in annexin V. When MVs are fused with planar phospholipid bilayers, a multiconductance Ca2+ channel is formed, with activity essentially identical to that observed when annexin V is delivered to the bilayer with phosphatidylserine liposomes. Ca2+ currents through this channel, from either MV or annexin V liposomes, are blocked by Zn2+, as is Ca2+ uptake by MV incubated in synthetic cartilage lymph. Blockage by Zn2+ was most effective when applied to the side containing the MV or liposomes. ATP and GTP differentially modulated the activity of this channel: ATP increased the amplitude of the current and the number of conductance states; GTP dramatically reduced the number of events and conductance states, leading to well-defined Ca2+ channel activity from either MV or the annexin V liposomes. In the distinctive effects of ATP, GTP, and Zn2+ on the Ca2+ channel activity observed in both the MV and the liposome systems, the common factor was the presence of annexin V. From this we conclude that Ca2+ entry into MV results from the presence of annexin V in these membrane-enclosed structures.