HCV NS4B targets Scribble for proteasome-mediated degradation to facilitate cell transformation.
Hepatitis C virus (HCV) nonstructural protein 4B (NS4B) is a multi-transmembrane protein, but little is known about how NS4B contributes to HCV replication and tumorigenesis. Its C-terminal domain (CTD) has been shown to associate with intracellular membrane, and we have previously shown that NS4B CTD contains a class I PDZ-binding motif (PBM). Here, we demonstrated that NS4B PBM interacts with the PDZ-containing tumor suppressor protein, Scribble, using immunofluorescence and co-immunoprecipitation assays, and this interaction requires at least three contiguous PDZ domains of Scribble. In addition, NS4B PBM specifically induced Scribble degradation by activating the proteasome-ubiquitin pathway. Similar Scribble degradation was also observed in HCV-infected cells, suggesting NS4B could work in the context of HCV. Finally, NS4B PBM mutants showed reduced colony formation capacity compared with its wild-type counterpart, indicating that NS4B PBM plays important roles in NS4B-mediated cell transformation. Altogether, we provide a mechanism by which NS4B induces cell transformation through its PBM, which specifically interacts with the PDZ domains of Scribble and targets Scribble for degradation.
Department of Laboratory Medicine, Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510630, China.
Bo
B
Hu
Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, College of Life Sciences, Hubei University, Wuhan, Hubei, 430062, China.
Shanshan
S
Li
Department of Laboratory Science, Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510120, China.
Zhanfeng
Z
Zhang
School of Laboratory Medicine, Hubei University of Chinese Medicine, Wuhan, Hubei, 430065, China.
Shenggao
S
Xie
School of Laboratory Medicine, Hubei University of Chinese Medicine, Wuhan, Hubei, 430065, China.
Yuqian
Y
Hu
Department of Laboratory Science, Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, 510120, China. huangxianzhanggd@126.com.
Xianzhang
X
Huang
School of Laboratory Medicine, Hubei University of Chinese Medicine, Wuhan, Hubei, 430065, China. zhengyi1205@126.com.|Department of Nephrology, Huadu District People's Hospital, Southern Medical University, Guangzhou, 510800, China. zhengyi1205@126.com.
Yi
Y
Zheng
D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002472:Cell Transformation, Viral; D057809:HEK293 Cells; D006367:HeLa Cells; D056945:Hep G2 Cells; D016174:Hepacivirus / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009154:Mutation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D011485:Protein Binding; D059748:Proteolysis; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*
D008565:Membrane Proteins; C080107:NS4B protein, flavivirus; C480591:SCRIB protein, human; D025521:Tumor Suppressor Proteins; D017361:Viral Nonstructural Proteins; D046988:Proteasome Endopeptidase Complex
HCV; NS4B; PBM; Scribble; Tumorigenesis; Ubiquitin