RESUMO
HIV type 1 (HIV-1) was shown to assemble either at the plasma membrane or in the membrane of late endosomes. Now, we report an essential role for human ubiquitin ligase POSH (Plenty of SH3s; hPOSH), a trans-Golgi network-associated protein, in the targeting of HIV-1 to the plasma membrane. Small inhibitory RNA-mediated silencing of hPOSH ablates virus secretion and Gag plasma membrane localization. Reintroduction of native, but not a RING finger mutant, hPOSH restores virus release and Gag plasma membrane localization in hPOSH-depleted cells. Furthermore, expression of the RING finger mutant hPOSH inhibits virus release and induces accumulation of intracellular Gag in normal cells. Together, our results identify a previously undescribed step in HIV biogenesis and suggest a direct function for hPOSH-mediated ubiquitination in protein sorting at the trans-Golgi network. Consequently, hPOSH may be a useful host target for therapeutic intervention.
Assuntos
HIV-1/fisiologia , Ubiquitina-Proteína Ligases/metabolismo , Replicação Viral/fisiologia , Rede trans-Golgi/enzimologia , Membrana Celular/enzimologia , Membrana Celular/virologia , Clonagem Molecular , Produtos do Gene gag/metabolismo , Inativação Gênica , Células HeLa , Humanos , Transporte Proteico , Proteínas Recombinantes/metabolismo , Ubiquitina-Proteína Ligases/genéticaRESUMO
The EFRH sequence, found to be the main anti-aggregating epitope corresponding to amino acids 3-6 of beta-amyloid peptide (AbetaP), was displayed on a phage and used as an antigen for immunization of mice, guinea pigs and rabbits. The generated antibodies recognize the full-length AbetaP (1-40) and exhibit similar biological properties to antibodies raised against whole soluble peptide and/or fibrillar beta-amyloid. EFRH-phage immunization of a transgenic mouse model of Alzheimer's disease evokes antibodies able to dissolve already formed beta-amyloid plaques, suggesting that they could become a therapeutic approach in treatment of the disease.
