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Claude
Krummenacher, Ph.D.
Assistant Professor,
Biochemistry
Microbiology,
Virology and Parasitology Program
Address
521 Levy Building(Office)
240 S. 40th Street
Philadelphia, PA 19104-6002
Office tel.: 215 898-6553
Lab tel.: 215 898-6553
Fax: 215 898-3695
E-mail: krumm@biochem. dental.upenn.edu
Link(s)
SDM
Department of Biochemistry
Education
University of Lausanne, Lusanne, Switzwerland
BS (Biology), 1990.
University of Lausane, Lausanne, Switzerland: Ph. D.(Virology),
1995.
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Research
Interests
Herpes simplex virus entry and cell-cell adhesion.
Key words: herpes, glycoprotein, receptor, nectin, cell adhesion,
virus entry, cell junctions.
Search PubMed for articles
Description
of Research
My
studies focus on the nectins, a family of cell adhesion molecules
used as receptors by neurotropic herpesviruses. My overall
goal is to understand how herpes simplex virus (HSV) uses
receptors from the nectin family for entry, spread and pathogenesis.
Toward that goal, three lines of research are being developed:
1. To determine
how HSV uses and subverts the normal functions of nectin-1 during
viral entry and spread.
2. To define how the cell responds when nectin-1 engages cellular
versus viral ligands.
3. To define how binding of nectin-1 to HSV gD triggers virus
entry
Members of the nectin family interact with each other at various
specialized cell contacts such as synapses in neurons or adherens junctions of the
epithelium. For instance, nectin-1 interacts with nectin-3 at synapses and plays a role
in ocular and craniofacial development. However, intracellular effects of ligand binding
to nectins remain mostly unknown. Nectin-1, and nectin-2 are used by HSV and other
alpha-herpesviruses to enter epithelial cells and neurons. The viral ligand for nectin-1
is the envelope glycoprotein D (gD) and this interaction is a crucial step for HSV entry.
At the molecular level, this interaction induces conformational changes in gD that activate
the complex mechanism leading to membrane fusion and entry. At the cellular level, gD interferes
with the ability of nectin-1 to mediate cell aggregation. This may be the
result of direct competition with nectin-1 natural ligands or by inducing an adverse
cellular response. My interest is to understand how nectin-1 mediates cell adhesion and
how HSV subverts this natural function during its entry into cells. I study interactions
between nectin-1 and gD at the molecular and structural levels using proteins purified
from the baculovirus expression system and cell models.
Studies of the mechanism of action and regulation of nectins at the cellular level are another facet
of my research. First, I am looking at the cellular responses to nectin-1 binding at cell contacts
during establishment of adherens junctions. Second I am looking at the signals mediated by nectin-1
during HSV infection. Recent developments in confocal live cell imaging make it possible to look directly
at nectins in situ.
Various cell lines expressing nectin-1 tagged with GFP, YFP and CFP have been generated to assess the response of nectins upon ligand binding in real time.
Recent
Publications
Krummenacher, C., A.Carfi,
R.J. Eisenberg and G.H. Cohen. Herpesvirus entry into cells:
The Enigma Variations. In S. Pöhlmann and G. Simmons, eds.
Viral entry into host cells. (2007). Landes Bioscience.
Vol. in press. Online edition: http://www.eurekah.com/chapter/3035
De Regge, N., H.J. Nauwynck, K. Geenen, C.
Krummenacher, G.H. Cohen, R.J. Eisenberg, T.C. Mettenleiter
and H.W. Favoreel. (2006). Alpha-herpes virus gD interaction
with sensory neurons triggers formation of varicosities that
serves as virus exit sites. J. Cell Biol. 174:267-275.
Krummenacher, C., V.M. Supekar,
J.C. Whitbeck, E. Lazear, S.C. Connolly, R.J. Eisenberg, G.H.
Cohen, D.C. Wiley and A. Carfi. (2005). Structure of unliganded
HSV gD reveals a mechanism for receptor-mediated activation
of virus entry. EMBO J. 24:4144-4153.
Krummenacher, C., F. Baribaud,
M. Ponce de Leon, I. Baribaud, J.C. Whitbeck, R. Xu, G.H.
Cohen and R.J. Eisenberg. (2004). Comparative usage of herpesvirus
entry mediator A and nectin-1 by laboratory strains and clinical
isolates of herpes simplex virus. Virology 332: 286-299.
Krummenacher, C., I. Baribaud, R.J. Eisenberg
and G.H. Cohen. (2003). Cellular localization of nectin-1 and
glycoprotein D during herpes simplex virus infection. J.
Virol. 77: 8985-8999.
Lab
Rotation
Projects
1. Analysis of the effects of HSV infection on cell junctions.
This project involves cell culture, transfections, confocal microscopy and HSV infection,
and will give the student training in virology and cell biology.
2. Analysis of the consequences of HSV gD binding to cells expressing nectin-1. This project includes
cell culture, transfections and confocal microscopy. Handling purified proteins will also be part of
this project involving training in cell biology and protein characterization.
3. Characterization of nectin-1 with its various ligands. This project involves cloning, production and purification of proteins in the baculovirus system. Purified proteins will be used in experiments in vitro (Western blot, ELISA, optical biosensor assays) as well as in cell culture (CELISA, virus entry assays)
and will give the student training in molecular biology, virology and protein biochemistry.
- Lab
personnel:
- Currently recruiting
last updated 6/2007
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