Enhances virion budding, by targeting human CD4 and Tetherin/BST2 to proteasome degradation. Degradation of CD4 prevents any unwanted premature interactions between viral Env and its receptor human CD4 in the endoplasmic reticulum. Degradation of antiretroviral protein Tetherin/BST2 is important for virion budding, as BST2 tethers new viral particles to the host cell membrane. Mechanistically, Vpu bridges either CD4 or BST2 to BTRC, a substrate recognition subunit of the Skp1/Cullin/F-box protein E3 ubiquitin ligase, induces their ubiquitination and subsequent proteasomal degradation. The alteration of the E3 ligase specificity by Vpu seems to interfere with the degradation of host IKBKB, leading to NF-kappa-B down-regulation and subsequent apoptosis By similarity.

Ion channel activity is inhibited by hexamethylene amiloride in vitro By similarity.

May form pentamers or hexamers. Forms ternary complexes, by interacting with human CD4 and BTRC, and with human BST2 and BTRC By similarity.

Host membrane; Single-pass type I membrane protein By similarity.

The N-terminal and transmembrane domains are required for proper virion budding, whereas the cytoplasmic domain is required for CD4 degradation. The cytoplasmic domain is composed of 2 amphipathic alpha helix By similarity.

Phosphorylated by host CK2. This phosphorylation is necessary for interaction with human BTRC and degradation of CD4 By similarity.

HIV-1 lineages are divided in three main groups, M (for Major), O (for Outlier), and N (for New, or Non-M, Non-O). The vast majority of strains found worldwide belong to the group M. Group O seems to be endemic to and largely confined to Cameroon and neighboring countries in West Central Africa, where these viruses represent a small minority of HIV-1 strains. The group N is represented by a limited number of isolates from Cameroonian persons. The group M is further subdivided in 9 clades or subtypes (A to D, F to H, J and K).

Belongs to the HIV-1 VPU protein family.

Inferred from electronic annotation. Source: UniProtKB-KW

Inferred from Experiment. Source: Reactome

Inferred from electronic annotation. Source: UniProtKB-KW

Inferred from electronic annotation. Source: UniProtKB-KW

Inferred from Experiment. Source: Reactome

Inferred from electronic annotation. Source: InterPro

Inferred from Experiment. Source: Reactome

Inferred from Experiment. Source: Reactome

Inferred from electronic annotation. Source: UniProtKB-SubCell

Inferred from electronic annotation. Source: UniProtKB-KW