title: The role of ITCH protein in human T-cell leukemia virus type 1 release.
abstract: Human T-cell leukemia virus type 1 (HTLV-1) has two late domain (LD) motifs, PPPY and PTAP, which are important for viral budding. Mutations in the PPPY motif are more deleterious for viral release than changes in the PTAP motif. Several reports have shown that the interaction of PPPY with the WW domains of a Nedd4 (neuronal precursor cell-expressed developmentally down-regulated-4) family ubiquitin ligase (UL) is a critical event in virus release. We tested nine members of the Nedd4 family ULs and found that ITCH is the main contributor to HTLV-1 budding. ITCH overexpression strongly inhibited release and infectivity of wild-type (wt) HTLV-1, but rescued the release of infectious virions with certain mutations in the PPPY motif. Electron microscopy showed either fewer or misshapen virus particles when wt HTLV-1 was produced in the presence of overexpressed ITCH, whereas mutants with changes in the PPPY motif yielded normal looking particles at wt level. The other ULs had significantly weaker or no effects on HTLV-1 release and infectivity except for SMURF-1, which caused enhanced release of wt and all PPPY(-) mutant particles. These particles were poorly infectious and showed abnormal morphology by electron microscopy. Budding and infectivity defects due to overexpression of ITCH and SMURF-1 were correlated with higher than normal ubiquitination of Gag. Only silencing of ITCH, but not of WWP1, WWP2, and Nedd4, resulted in a reduction of HTLV-1 budding from 293T cells. The binding efficiencies between the HTLV-1 LD and WW domains of different ULs as measured by mammalian two-hybrid interaction did not correlate with the strength of their effect on HTLV-1 budding.
authors: HIV-Drug Resistance Program, NCI Frederick, Frederick, Maryland 21702, USA.
authors: Batsukh
authors: B
authors: Dorjbal
authors: David
authors: D
authors: Derse
authors: Patricia
authors: P
authors: Lloyd
authors: Ferri
authors: F
authors: Soheilian
authors: Kunio
authors: K
authors: Nagashima
authors: Gisela
authors: G
authors: Heidecker
mesh_terms: D020816:Amino Acid Motifs / Q000235:genetics; D002460:Cell Line; D056827:Endosomal Sorting Complexes Required for Transport; D015683:Gene Products, gag / Q000378:metabolism; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008854:Microscopy, Electron; D000075702:Nedd4 Ubiquitin Protein Ligases; D012097:Repressor Proteins / Q000502:physiology*; D044767:Ubiquitin-Protein Ligases / Q000502:physiology*; D054875:Ubiquitination; D057074:Virus Release
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D015683:Gene Products, gag; D012097:Repressor Proteins; C432966:ITCH protein, human; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618483:Nedd4 protein, human; C498342:SMURF1 protein, human; C471642:WWP1 protein, human; C465283:WWP2 protein, human; D044767:Ubiquitin-Protein Ligases