Volker Vogt, PhD
Department of Microbiology and Immunology
Volker Vogt is a Professor of Biochemistry, Molecular and Cell Biology and has been on the Cornell faculty since 1976. He obtained his BS in chemistry from CalTech, PhD in biochemistry and molecular biology from Harvard, and was a post doctoral fellow at the Swiss Institute for Experimental Cancer Research before joining the faculty at Cornell. In 1992-1993 he was a Senior Fogarty Fellow while on sabbatical leave at the Germany Cancer Research Center in Heidelberg. Vogt is currently Director of Graduate Studies in the Field of Biochemistry, Molecular and Cell Biology.
Research Interests
The major research focus in our lab is the structure and assembly of retroviruses, with the avian sarcoma and leukemia viruses (ASLV, prototype Rous sarcoma virus) as the primary model system. In the present day, this work is most relevant to HIV, and we also include HIV genes in some of our studies. Like many other enveloped viruses, retroviruses are formed under the plasma membrane of the infected cell, emerging by budding - i.e. wrapping themselves in a piece of membrane derived from the host cell. Protein-protein interactions, protein-lipid interactions, and protein-RNA interactions are involved in this process. Expression of the internal structural protein of retroviruses, called Gag, leads to the budding of morphologically normal, immature virus-like particles (VLPs) from the plasma membrane, thus defining Gag as the key player in assembly. The final or "maturation" step in formation of an infectious retrovirus particle, which occurs in the last stages or just after assembly, is the cleavage of Gag and of the enzymatic protein precursor, Pol, by the viral protease. Cleavage leads to morphological and biochemical changes in the virus particle.
Many questions about retrovirus assembly remain unanswered. For example: How does the Gag protein recognize and bind to the plasma membrane, and how does the viral membrane acquire its unusual ‘raft-like’ lipid composition? What roles do cell proteins play in assembly and budding? What molecular interactions between Gag molecules occur during the ‘polymerization’ that leads to the formation of a spherical protein shell composed of over a thousand Gag molecules? How is the genomic viral RNA recognized and encapsidated? By what means is proteolytic cleavage regulated? The methods that we use to address such questions include in vitro mutagenesis; expression of viral proteins in a variety of cells; purification and analysis of virus particles; assays of enzymatic activities; protein-RNA and protein-lipid binding studies; fluorescence microscopy and electron microscopy; and in vitro assembly of virus-like particles from proteins purified after expression in E. coli. These studies thus straddle molecular biology and cell biology. We have ongoing collaborations with structural biologists and other retrovirologists, both at Cornell and at other institutions in the US and abroad.