Assembly with the Cul4A-DDB1-DCAF1 ubiquitin ligase protects HIV-1 Vpr from proteasomal degradation Export

@article{citeulike:2875090, abstract = {Many viruses subvert the host ubiquitin-proteasome system to optimize their life cycle. We recently documented such a mechanism for the HIV-1 Vpr protein, which promotes cell cycle arrest by recruiting the DCAF1 adaptor of the Cul4A-DDB1 ubiquitin ligase, a finding now confirmed by several groups. Here we examined the impact of Cul4A-DDB1DCAF1 on Vpr stability. We show that the Vpr Q65R mutant, which is defective in DCAF1 binding, undergoes proteasome-mediated degradation at a higher rate than wild-type Vpr. DCAF1 overexpression stabilizes Vpr wt and leads to its cytoplasmic accumulation, whereas it has no effect on the Vpr Q65R mutant. Conversely siRNA-mediated silencing of DCAF1 decreases the steady state amount of the viral protein. Stabilization by DCAF1, which is conserved by Vpr species from HIV-2 and SIVmac, results in increased G2 arrest and requires the presence of DDB1, indicating that it occurs through assembly of Vpr with a functional Cul4A-DDB1DCAF1 complex. Furthermore in HIV-1 infected cells, the Vpr protein, issued from the incoming viral particle, is destabilized under DCAF1 or DDB1 silencing. Together with our previous findings, our data suggest that Cul4A-DDB1DCAF1 acts at a dual level by providing Vpr with the equipment for the degradation of specific host proteins and by counteracting its proteasome targeting by another cellular E3 ubiquitin ligase. This protection mechanism may represent an efficient way to optimize the activity of Vpr molecules that are delivered by the incoming virus before neosynthesis takes place. Targeting the Vpr-DCAF1 interaction might therefore present therapeutic interest. 10.1074/jbc.M710298200}, author = {Le Rouzic, Erwann and Morel, Marina and Ayinde, Diana and Belaidouni, Nadia and Letienne, Justine and Transy, Catherine and Margottin-Goguet, Florence}, citeulike-article-id = {2875090}, citeulike-linkout-0 = {http://dx.doi.org/10.1074/jbc.M710298200}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/18524771}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=18524771}, day = {4}, doi = {10.1074/jbc.M710298200}, journal = {J. Biol. Chem.}, keywords = {ubiquitin, vpr}, month = {June}, pages = {M710298200+}, posted-at = {2008-06-09 10:34:38}, priority = {2}, title = {Assembly with the Cul4A-DDB1-DCAF1 ubiquitin ligase protects HIV-1 Vpr from proteasomal degradation}, url = {http://dx.doi.org/10.1074/jbc.M710298200}, year = {2008} }

TY - JOUR ID - citeulike:2875090 L3 - citeulike-article-id:2875090 N2 - Many viruses subvert the host ubiquitin-proteasome system to optimize their life cycle. We recently documented such a mechanism for the HIV-1 Vpr protein, which promotes cell cycle arrest by recruiting the DCAF1 adaptor of the Cul4A-DDB1 ubiquitin ligase, a finding now confirmed by several groups. Here we examined the impact of Cul4A-DDB1DCAF1 on Vpr stability. We show that the Vpr Q65R mutant, which is defective in DCAF1 binding, undergoes proteasome-mediated degradation at a higher rate than wild-type Vpr. DCAF1 overexpression stabilizes Vpr wt and leads to its cytoplasmic accumulation, whereas it has no effect on the Vpr Q65R mutant. Conversely siRNA-mediated silencing of DCAF1 decreases the steady state amount of the viral protein. Stabilization by DCAF1, which is conserved by Vpr species from HIV-2 and SIVmac, results in increased G2 arrest and requires the presence of DDB1, indicating that it occurs through assembly of Vpr with a functional Cul4A-DDB1DCAF1 complex. Furthermore in HIV-1 infected cells, the Vpr protein, issued from the incoming viral particle, is destabilized under DCAF1 or DDB1 silencing. Together with our previous findings, our data suggest that Cul4A-DDB1DCAF1 acts at a dual level by providing Vpr with the equipment for the degradation of specific host proteins and by counteracting its proteasome targeting by another cellular E3 ubiquitin ligase. This protection mechanism may represent an efficient way to optimize the activity of Vpr molecules that are delivered by the incoming virus before neosynthesis takes place. Targeting the Vpr-DCAF1 interaction might therefore present therapeutic interest. 10.1074/jbc.M710298200 JF - J. Biol. Chem. TI - Assembly with the Cul4A-DDB1-DCAF1 ubiquitin ligase protects HIV-1 Vpr from proteasomal degradation SP - M710298200 KW - ubiquitin KW - vpr AU - Le Rouzic, Erwann AU - Morel, Marina AU - Ayinde, Diana AU - Belaidouni, Nadia AU - Letienne, Justine AU - Transy, Catherine AU - Margottin-Goguet, Florence PY - 2008/06/04/ UR - http://dx.doi.org/10.1074/jbc.M710298200 ER -