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Associate Professor of BiologyAssociate Professor of
Molecular Physiology and Biophysics
Office: 236 BBEIowa City, IA 52242
Email: firstname.lastname@example.orgWeb: More About Dr. Stipp - Related Websites and Resources
BS, Biochemistry, Indiana UniversityPhD, Biology, Massachusetts Institute of Technology
Biosciences Graduate ProgramInterdisciplinary Graduate Program in NeuroscienceMedical Scientist Training Program
Cell Biology: Cell Surface interaction maps and cell migration cues in the extracellular microenvironment govern the behavior of migrating cells by triggering changes in migration speed or direction. The cell surface receptors that interpret these cues engage cytoplasmic partners to transduce signals, but recent work reveals that many receptors also interact with cell surface proteins that can be critical for proper receptor function. Thus, a more sophisticated understanding of cell migration will require a ""cell surface interaction map"" describing the connectivity of receptors and their cell surface partners.
To begin to build such an interaction map, we are studying members of the tetraspanin family of cell surface adaptor proteins. Tetraspanins organize complexes containing integrins (major receptors for extracellular matrix proteins), lg superfamily (lgSF) proteins, growth factor receptors, membrane-bound growth factors, and novel proteins. By targeting tetraspanins, which lie at the center of these complexes, a large number of new cell surface interactions can be uncovered at once.
Three types of projects are ongoing in the lab. First, we are continuing to identify the components of tetraspanin complexes. These studies have the potential to reveal novel physical and functional connections between diverse cell surface proteins. Second, we are mapping key interaction sites within tetraspanin complexes required for their formation and maintenance. Here we are focusing on two complexes organized by tetraspanins CD9 and CD81. In the first complex, tetraspanins CD9 and CD81 link a3b1 integrin (a receptor for the extracellular matrix protein, laminin-5) to lgSF proteins EWI-2 and EWI-F (FPRP) (top panel at right). In the second complex, CD9 and CD81 promote the association of GPR56, a G-protein coupled receptor, with Ga and Gbg cytoplasmic signaling components (bottom panel at right). Third, we are developing methods for perturbing tetraspanin complexes and testing the effects on two important types of cell motility: carcinoma cell migration and neurite regeneration in neuronal cells. The information we uncover may ultimately contribute to strategies for inhibiting tumor cell metastasis or encouraging the re-growth of damaged nerves. For example, we recently found that by over-expressing EWI-2 we can severely impair a3b1 integrin-dependent carcinoma cell motility on laminin-5.
Date Last Modified: 08/04/2015 -
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