Ubiquitin-fusion as a strategy to modulate protein half-life: A3G antiviral activity revisited.
Virology
; 393(2): 286-94, 2009 Oct 25.
Article
in En
| MEDLINE
| ID: mdl-19717177
ABSTRACT
The human APOBEC3G (A3G) is a potent inhibitor of HIV-1 replication and its activity is suppressed by HIV-1 virion infectivity factor (Vif). Vif neutralizes A3G mainly by inducing its degradation in the proteasome and blocking its incorporation into HIV-1 virions. Assessing the time needed for A3G incorporation into virions is, therefore, important to determine how quickly Vif must act to induce its degradation. We show that modelling the intracellular half-life of A3G can induce its Vif-independent targeting to the ubiquitin-proteasome system. By using various amino acids (X) in a cleavable ubiquitin-X-A3G fusion, we demonstrate that the half-life (t1/2) of X-A3G can be manipulated. We show that A3G molecules with a half-life of 13 min are incorporated into virions, whereas those with a half-life shorter than 5 min were not. The amount of X-A3G incorporated into virions increases from 13 min (Phe-A3G) to 85 min (Asn-A3G) and remains constant after this time period. Interestingly, despite the presence of similar levels of Arg-A3G (t1/2=28 min) and Asp-A3G (t1/2=65 min) into HIV-1 Deltavif virions, inhibition of viral infectivity was only evident in the presence of A3G proteins with a longer half-life (t1/2 > or = 65 min).
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Cytidine Deaminase
/
Ubiquitin
/
Vif Gene Products, Human Immunodeficiency Virus
Type of study:
Prognostic_studies
Limits:
Humans
Language:
En
Journal:
Virology
Year:
2009
Document type:
Article
Affiliation country: