Schwartz M D, Geraghty R J, Panganiban A T
McArdle Laboratory for Cancer Research, University of Wisconsin, Medical School, Madison 53706, USA.
Virology. 1996 Oct 1;224(1):302-9. doi: 10.1006/viro.1996.0532.
Vpu and the C-terminal peptide of Gag (p6) are both HIV-1-encoded proteins that augment the release of virus particles from cells. We examined the functional relationship between these proteins and their activities during particle release. Our results indicate that efficient HIV-1 particle release from HeLa and Jurkat cells depends on the presence of Vpu. However, Vpu is dispensable for efficient release from Cos cells. In contrast, p6 is required for efficient release from Cos cells but not from Jurkat or HeLa cells. These data suggest that Vpu and p6 have distinct activities in virus exit from different cell lines. Intracellular proteolytic processing of Gag precursor protein is more complete in Cos cells than in HeLa cells. However, this processing has little or no effect on Vpu- or p6-mediated particle release. p6 is required for incorporation of yet another virus protein (Vpr) into cells but our data suggest that Vpr plays no role in p6-dependent particle release. Vpu also facilitates the degradation of CD4 in virus producing cells but, in contrast to particle release, the ability of Vpu to facilitate the degradation of CD4 is not cell line-dependent.
Vpu和Gag的C末端肽（p6）都是HIV-1编码的蛋白质，它们可增强病毒颗粒从细胞中的释放。我们研究了这些蛋白质之间的功能关系及其在颗粒释放过程中的活性。我们的结果表明，从HeLa细胞和Jurkat细胞中有效释放HIV-1颗粒取决于Vpu的存在。然而，Vpu对于从Cos细胞中有效释放是可有可无的。相反，p6是从Cos细胞中有效释放所必需的，但从Jurkat细胞或HeLa细胞中释放则不需要。这些数据表明，Vpu和p6在病毒从不同细胞系中释放时具有不同的活性。Gag前体蛋白在Cos细胞中的细胞内蛋白水解加工比在HeLa细胞中更完整。然而，这种加工对Vpu或p6介导的颗粒释放几乎没有影响。p6是另一种病毒蛋白（Vpr）掺入细胞所必需的，但我们的数据表明Vpr在p6依赖性颗粒释放中不起作用。Vpu还促进病毒产生细胞中CD4的降解，但与颗粒释放相反，Vpu促进CD4降解的能力不依赖于细胞系。
