Kouacou Konan Assistant Professor of Biochemistry and Molecular Biology 308 Althouse Laboratory, University Park, PA 16802 Phone: (814) 863-8254 Fax: (814) 863-7024 E-mail: kvk10@psu.edu M.A. in Microbiology & Molecular Biology from Indiana University Ph.D. in Microbiology & Molecular Biology from Indiana University Postdoctoral, Stanford University of California Konan Lab Web Site

Hepatitis C and related viruses: understanding the role of intracellular membrane rearrangement in the replication of these viruses

        Hepatitis C virus (HCV) is a positive-stranded RNA virus of the family Flaviviridae, including Dengue virus, West Nile virus, and bovine viral diarrhea virus. HCV is a leading cause of liver cancer worldwide. The long-term goal of this laboratory is to understand how HCV and related viruses exploit the function and ultrastructure of host secretory apparatus for their own replication. Specifically, my lab is interested in the role that HCV-induced intracellular membranes play in viral genome replication.

        Like many positive stranded RNA viruses, HCV replicates in the cytoplasm of infected cells, resulting in the formation of rearranged membranes called webs. These novel membranes are proposed to be the site of viral RNA replication. One of the projects in the lab focuses on determining the intracellular origin of the webs; we believe that a better understanding of the cellular origin of these membranes will help us to propose the direct or indirect role that these membranes play in HCV life cycle.

Mechanism of formation of the membranous webs induced by HCV

        Our current working model states that HCV NS4B, the web-inducing viral protein, oligomerizes; this oligomerization brings endoplasmic reticulum (ER)-derived vesicles together to initiate webs formation. We have evidence suggesting that the webs have a more complex origin, including the ER and perhaps the early endosome compartment. We are currently using a variety of approaches including electron microscopy, biochemical isolation of the webs and proteomics to understand the complexity of this novel intracellular membrane and their role in HCV genome replication and assembly.

Using bovine viral diarrhea virus (BVDV) and Dengue virus as model systems to understand HCV replication

        BVDV and Dengue virus cause serious diseases that are often fatal in cattle and humans respectively. Unlike HCV, these viruses are easier to propagate in tissue culture cells in comparison to HCV; they therefore provide useful models for understanding HCV replication in vitro. My laboratory is interested in understanding how BVDV or Dengue virus replication affects protein and membrane trafficking and which viral proteins are involved in the process. We would like to generate mutant viruses and examine their phenotypes both in cell culture and in transgenic mice model. Finally, we are interested in creating recombinant BVDV expressing HCV NS4B to determine whether HCV NS4B supports BVDV replication and induces web formation during HCV replication. Such a chimeric virus will allow us to examine how different NS4B mutations affect virus genome replication and virus production.

HCV and inhibition of host protein transport

        In an attempt to determine how HCV might cause persistent infection in patients, I have shown that HCV precursor protein NS4AB, or full-length viral genome, interferes with host protein traffic in a nonspecific manner. These findings suggest that inhibition of host protein transport by HCV NS4AB is biologically relevant. The NS4AB residues responsible for traffic inhibition are not known nor do we know which cellular factors are involved in that process. It is not clear whether NS4B, the web-inducing protein, also inhibits host protein traffic. Finally, we do not know how widespread this inhibition of protein transport is among different HCV genotypes.

Representative Publications:

• Konan, K.V., T.H. Giddings, Jr., M. Ikeda, K. Li, S.M. Lemon, and K. Kirkegaard. 2003. Nonstructural    protein precursor NS4A/B from hepatitis C virus alters function and ultrastructure of host secretory apparatus. J. Virol. 77, 7843-7855.
• Stone, M., S. Jia, W.D. Heo, T. Meyer, and K.V. Konan. 2007. Participation of Rab5, an early endosome protein, in hepatitis C virus RNA replication machinery. J. Virol. 81, 4551-4563.

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