Figure 1

Schematic representations of Vpu. (A) Predicted secondary and tertiary structure of Vpu showing the N-terminal transmembrane domain (TM) and the two α-helices of the cytoplasmic (CYTO) domain. The numbers indicate amino acid positions of the NL4.3 prototypical Vpu allele. In both panels, yellow circles represent phosphorylated serine residues (S52 and S56) sites. The 13° tilt angle of the TM domain is indicated. (B) Vpu topology with the corresponding HIV-1/SIVcpz Ptt Vpu consensus sequences (HIV sequence database, http://www.hiv.lanl.gov). Question marks indicate residues with no consensus available. The red box indicates the conserved sequences recognized by β-TrCP. The blue boxes highlight areas containing putative trafficking signals shown below. X and Φ correspond to variable and hydrophobic amino-acid residues, respectively. αH: α-helix.