Molecular cloning and characterization of the von Hippel-Lindau-like protein.
von Hippel-Lindau (VHL) tumor suppressor protein-inactivated in VHL disease and sporadic kidney cancer-is a component of an E3 ubiquitin ligase complex that selectively ubiquitinates the alpha subunit of the hypoxia-inducible factor (HIF) transcription factor for subsequent destruction by the 26S proteasome. Here, we report the identification and characterization of the first VHL homologue, VHL-like protein (VLP), located on chromosome 1q21.2. A 676-bp partial cDNA encoding a 139-amino acid protein that is 78% similar to VHL was isolated by reverse transcription-PCR from human brain cerebellum and several cancer cell lines. The expression of VLP transcript is most abundant in the placenta. Like VHL, VLP contains a beta domain capable of binding HIFalpha. However, unlike VHL, it does not contain a recognizable alpha domain, which is required for nucleating the multiprotein E3 ubiquitin ligase complex. The increased expression of VLP in the presence of VHL attenuated the ubiquitination of HIFalpha and led to the accumulation of downstream HIF target genes. These results taken together indicate that VLP functions as a dominant-negative VHL to serve as a protector of HIFalpha.
Qi
Heng
H
Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.
Gervais
Michelle L
ML
Li
Wei
W
DeCaprio
James A
JA
Challis
John R G
JR
Ohh
Michael
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D002531:Cerebellum / Q000378:metabolism; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D016147:Genes, Tumor Suppressor; D006801:Humans; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D015151:Immunoblotting; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D010920:Placenta / Q000378:metabolism; D011233:Precipitin Tests; D046988:Proteasome Endopeptidase Complex; D011869:Radioligand Assay; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D006623:von Hippel-Lindau Disease / Q000235:genetics
D004268:DNA-Binding Proteins; C497442:HIF1A protein, human; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease; C497446:VHL protein, human