The TRC8 hereditary kidney cancer gene suppresses growth and functions with VHL in a common pathway.
VHL is part of an SCF related E3-ubiquitin ligase complex with 'gatekeeper' function in renal carcinoma. However, no mutations have been identified in VHL interacting proteins in wild type VHL tumors. We previously reported that the TRC8 gene was interrupted by a t(3;8) translocation in a family with hereditary renal and non-medullary thyroid cancer. TRC8 encodes a multi-membrane spanning protein containing a RING-H2 finger with in vitro ubiquitin ligase activity. We isolated the Drosophila homologue, DTrc8, and studied its function by genetic manipulations and a yeast 2-hybrid screen. Human and Drosophila TRC8 proteins localize to the endoplasmic reticulum. Loss of either DTrc8 or DVhl resulted in an identical ventral midline defect. Direct interaction between DTrc8 and DVhl was confirmed by GST-pulldown and co-immunoprecipitation experiments. CSN-5/JAB1 is a component of the COP9 signalosome, recently shown to regulate SCF function. We found that DTrc8 physically interacts with CSN-5 and that human JAB1 localization is dependent on VHL mutant status. Lastly, overexpression of DTrc8 inhibited growth consistent with its presumed role as a tumor suppressor gene. Thus, VHL, TRC8, and JAB1 appear to be linked both physically and functionally and all three may participate in the development of kidney cancer.
Gemmill
Robert M
RM
Division of Medical Oncology, University of Colorado Health Sciences Center, 4200 E. 9th Avenue, Denver, Colorado, CO 80262, USA. robert.gemmill@uchsc.edu
Bemis
Lynne T
LT
Lee
Jason P
JP
Sozen
M Ali
MA
Baron
Anna
A
Zeng
Chan
C
Erickson
Paul F
PF
Hooper
Joan E
JE
Drabkin
Harry A
HA
D016475:3T3 Cells; D000818:Animals; D000075686:COP9 Signalosome Complex; D019556:COS Cells; D002292:Carcinoma, Renal Cell / Q000235:genetics; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000032:analysis; D004330:Drosophila / Q000737:chemistry / Q000196:embryology; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000737:chemistry; D005260:Female; D016147:Genes, Tumor Suppressor; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007680:Kidney Neoplasms / Q000235:genetics; D008025:Ligases / Q000235:genetics / Q000502:physiology*; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D010447:Peptide Hydrolases; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface; D015398:Signal Transduction; D014157:Transcription Factors / Q000032:analysis; D025521:Tumor Suppressor Proteins; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D014921:Wings, Animal / Q000196:embryology
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C114025:RNF139 protein, human; D011956:Receptors, Cell Surface; C456159:TRC8 protein, Drosophila; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D044767:Ubiquitin-Protein Ligases; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D010447:Peptide Hydrolases; C501488:COPS5 protein, human; C501491:CSN5 protein, Drosophila; C501490:Cops5 protein, mouse; D000075686:COP9 Signalosome Complex; D008025:Ligases; C497446:VHL protein, human