Figure 5

Vpu cannot degrade CD317 in β-TrCP2-depleted cells, but still enhances HIV-1 release. 293TCD4 cells were transfected twice with siRNAs targeting either β-TrCP1 or β-TrCP2, or with a control siRNA, and during the second transfection, plasmids encoding HIV-1wt or HIV-1Δvpu, and HA-CD317 were added. Two days post-transfection, (A) the yield of infectious HIV-1 in culture supernatants was quantified. The arithmetic means ± SEM of six independent experiments are shown. (B, C) Transfected cells from (A) were processed for microscopic analysis to (C) visualize and (B) quantify the percentage of p24CA-positive (green) cells that no longer express HA-CD317 (red). In cells transfected with the specific siRNAs, remaining mRNA levels for β-TrCP1 and β-TrCP2 were 19 ± 4% and 13 ± 2%, respectively, relative to the control siRNA-treated cells. (B) The arithmetic means ± SEM of three independent experiments are shown. (C) Arrow heads indicate plasma membrane or intracellular p24CA⁺ aggregates. White arrows indicate HA-CD317 expression in p24CA⁺ cells. Scale bar: 10 μm.