Human immunodeficiency virus type 1 protease triggers a myristoyl switch that modulates membrane binding of Pr55gag and p17MA
Human immunodeficiency virus type 1 protease triggers a myristoyl switch that modulates membrane binding of Pr55gag and p17MA
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DOI：
10.1128/jvi.73.3.1902-1908.1999
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发表时间：
1999-03-01
影响因子：
5.4
通讯作者：
Resh, MD
中科院分区：
文献类型：
--
作者：
Hermida-Matsumoto, L;Resh, MD
人类免疫缺陷病毒I型（HIV-1）pr 55（gag）基因产物指导病毒体在细胞质膜内表面的组装。通过pr 55（gag）的质膜结合的特异性由N-末端肉豆蔻酰基部分和碱性残基富集结构域的组合赋予。虽然肉豆蔻酸加碱性结构域也存在于pr 55（gag）成熟后形成的p17 MA蛋白水解产物中，但p17 MA与膜结合的能力显著降低。先前报道，p17 MA的膜结合减少是由于肉豆蔻酰开关螯合肉豆蔻酸部分（W. Zhou和M. D. Resh，J. Virol. 70：8540-8548，1996），在此我们直接证明了用HIV-1蛋白酶原位处理膜结合的Pr 55（gag）产生p17 MA，然后将其从膜释放。Pr 55（gag）在网织红细胞裂解物中合成，结合到膜上，并与纯化的HIV-1蛋白酶孵育。在蛋白水解后分析膜结合和可溶性级分中的p17 MA产物。新产生的p17 MA最初是膜结合的，但随后显示出缓慢的时间依赖性解离，导致65%的溶解。残留的p17 MA可以从高pH或高盐的膜中提取。用蛋白酶处理转染COS-1细胞的膜，发现pr 55（gag）存在于密封的膜囊泡内，并且只有在加入去污剂和盐时才释放p17 MA。我们提出了一个模型，提出HIV-1蛋白酶是肉豆蔻酰开关机制的“触发器”，该机制调节pr 55（gag）和p17 MA在病毒体和膜的膜协会。
The human immunodeficiency virus type I (HIV-1) pr55(gag) gene product directs the assembly of virions at the inner surface of the cell plasma membrane. The specificity of plasma membrane binding by pr55(gag) is conferred by a combination of an N-terminal myristoyl moiety and a basic residue-rich domain. Although the myristate plus basic domain is also present in the p17MA proteolytic product formed upon pr55(gag) maturation, the ability of p17MA to bind to membranes is significantly reduced. It was previously reported that the reduced membrane binding of p17MA was due to sequestration of the myristate moiety by a myristoyl switch (W. Zhou and M. D. Resh, J. Virol. 70:8540-8548, 1996), Here we demonstrate directly that treatment of membrane-bound Pr55(gag) in situ with HIV-1 protease generates p17MA, which is then released from the membrane. Pr55(gag) was synthesized in reticulocyte lysates, bound to membranes, and incubated with purified HIV-1 protease, The p17MA product in the membrane-bound and soluble fractions was analyzed following proteolysis. Newly generated p17MA initially was membrane bound but then displayed a slow, time-dependent dissociation resulting in 65% solubilization. Residual p17MA could be extracted from the membranes with either high pH or high salt. Treatment of membranes from transfected COS-1 cells with protease revealed that pr55(gag) was present within sealed membrane vesicles and that the release of p17MA occurred only when detergent and salt were added. We present a model proposing that the HIV-1 protease is the "trigger" for a myristoyl switch mechanism that modulates the membrane associations of pr55(gag) and p17MA in virions and membranes.