Viral protein U (Vpu) is a protein encoded by human immunodeficiency virus type 1 (HIV-1) that promotes the degradation of the virus receptor, CD4, and enhances the release of virus particles from cells. We isolated a cDNA that encodes a novel cellular protein that interacts with Vpu in vitro, in vivo, and in yeast cells. This Vpu-binding protein (UBP) has a molecular mass of 41 kDa and is expressed ubiquitously in human tissues at the RNA level. UBP is a novel member of the tetratricopeptide repeat (TPR) protein family containing four copies of the 34-amino-acid TPR motif. Other proteins that contain TPR motifs include members of the immunophilin superfamily, organelle-targeting proteins, and a protein phosphatase. UBP also interacts directly with HIV-1 Gag protein, the principal structural component of the viral capsid. However, when Vpu and Gag are coexpressed, stable interaction between UBP and Gag is diminished. Furthermore, overexpression of UBP in virus-producing cells resulted in a significant reduction in HIV-1 virion release. Taken together, these data indicate that UBP plays a role in Vpu-mediated enhancement of particle release.

The efficient exit of HIV-1 particles from cells requires the action of the viral encoded protein Vpu. Vpu-binding protein (Ubp) is a cellular protein that interacts with both Vpu and the major structural component of the viral capsid (Gag) and appears to affect the efficiency of particle exit. Elucidation of the function of Ubp and characterization of the spatial distribution of Ubp may provide information pertinent to understanding the role of Ubp in virus replication. To investigate the subcellular location of Ubp, and to see whether Vpu affects the intracellular distribution of Gag, we carried out immunofluorescence localization in conjunction with confocal microscopy. Based on this analysis Ubp is present in both the nucleus and the cytoplasm. In the cytoplasm, Ubp appeared to be associated with microtubules as evidenced by cofluorescence with tubulin in the absence and in the presence of colchicine. However, cytoskeletal isolation and detergent extraction of cells resulted in association of Ubp with the soluble fractions, indicating that Ubp is not in tight association with microtubules. Moreover, flotation gradient analysis demonstrated that Ubp is cytoplasmic and not stably associated with the plasma membrane. Interestingly, expression of Vpu in cells resulted in redistribution of both Ubp and Gag to a location near the periphery of the cell. The effect of Vpu on both Ubp and Gag protein has implications for Vpu-mediated particle exit from cells.

Jugglers-Initiates-Hypnotism-Telepathy-Indian impressions,. 286 Index, 297 ROUGHING IT IN SOUTHERN INDIA for breakfast ; who sits before a flat, hollowed stone with another-a round one-in her hands, grinding the freshmint chutneys, and the curry powders and paste. What can she not put into them ? unless, as is very likely the case, she is grinding her own at the same time and requires ingredients for them also. From the least to the greatest, every one is at the mercy of the tunny-ketch. Such work as she does is infra dig. for a man ; the cook would scorn it. Yet, let a master be in difficulties, say he is an ill-paid bachelor, or a man trying to send home money to wife and children, living as best he can, managing on a tenth of his pay with one servant, and everything will be done for him ; his curry will be spicy, his rice white, with never a stone in it ; he knows not how, he does not ask. The truth is these people are contradictions, but they win respect, in some cases even love. Not all, however. One morning when we were staying at a friend's house the tea was very nasty, with what is called ' couch ' about it, that is a twang, half-taste, half-smell ; it was sent away that fresh might be made, but that proved just as bad, quite unaccountably. The next minute some commotion was heard, and the tunny-ketch came running from the back regions, holding her hands behind her, and crying out that she had been burnt by ' chinna putti Cyril Doray ' (little

Viral protein U (Vpu) is a protein encoded by human immunodeficiency virus type 1 (HIV-1) that promotes the degradation of the virus receptor, CD4, and enhances the release of virus particles from cells. We isolated a cDNA that encodes a novel cellular protein that interacts with Vpu in vitro, in vivo, and in yeast cells. This Vpu-binding protein (UBP) has a molecular mass of 41 kDa and is expressed ubiquitously in human tissues at the RNA level. UBP is a novel member of the tetratricopeptide repeat (TPR) protein family containing four copies of the 34-amino-acid TPR motif. Other proteins that contain TPR motifs include members of the immunophilin superfamily, organelle-targeting proteins, and a protein phosphatase. UBP also interacts directly with HIV-1 Gag protein, the principal structural component of the viral capsid. However, when Vpu and Gag are coexpressed, stable interaction between UBP and Gag is diminished. Furthermore, overexpression of UBP in virus-producing cells resulted in a significant reduction in HIV-1 virion release. Taken together, these data indicate that UBP plays a role in Vpu-mediated enhancement of particle release.

Urokinase-type plasminogen activator (uPA), a proteinase which activates plasminogen by cleaving at-CPGR2V-, was shown to cleave the V3 loop in recombinant gp120 of human immunodeficiency virus type 1 (HIV-1) IIIB and MN strains, as well as a synthetic, cyclized peptide representing the clade B consensus sequence of V3. Proteolysis occurred at the homologous-GPGR2A-, an important neutralizing determinant of HIV-1. It required soluble CD4 and was prevented by inhibitors of uPA but not by inhibitors of likely contaminating plasma proteinases. It was accelerated by heparin, a known cofactor for plasminogen activation. In immune capture experiments, tight binding of uPA to viral particles, which did not depend on CD4, was also demonstrated. Active site-directed inhibitors of uPA diminished this binding, as did a neutralizing antibody to V3. Addition of exogenous uPA to the laboratory-adapted IIIB strain of HIV-1, the macrophage-tropic field strains JR-CSF and SF-162, or a fresh patient isolate of indeterminate tropism, followed by infection of macrophages with the various treated viruses, resulted in severalfold increases in subsequent viral replication, as judged by yields of reverse transcriptase activity and p24 antigen, as well as incorporation, as judged by PCR in situ. These responses were reversible by inhibitors or antibodies targeting the proteinase active site or the V3 loop. We propose that uPA, a transcriptionally regulated proteinase which is upregulated when macrophages are HIV infected, can be bound and utilized by the virus to aid in fusion and may be an endogenous component that is critical to the infection of macrophages by HIV-1.