Assistant Professor

Publications | Research | Faculty

607-255-1016
jcf14@cornell.edu
457 Weill Hall

Background: 

Chris Fromme is an Assistant Professor in the Weill Institute for Cell and Molecular Biology and the Department of Molecular Biology and Genetics.  After graduating from Cornell with a B.A. in Biology in 1999, Chris did his graduate studies at Harvard University, receiving a Ph.D. in Biochemistry in 2004.  He then did postdoctoral work as a Miller Institute Fellow at UC Berkeley, where he began his work on how coat protein complexes control protein trafficking and membrane transport.  He joined the Cornell faculty in 2008.

Our lab is interested in how proteins and membranes are trafficked within eukaryotic cells.  Regulated transport of proteins between distinct membrane bound compartments is crucial for maintaining the homeostatic balance of the endomembrane system.  Most transport events are governed by soluble cytoplasmic protein complexes called “coats” that function both as receptors for transported proteins and also as structural supports for deforming membranes into transport carriers (such as vesicles).  Therefore, coat proteins provide both a mechanical and biochemical means for transport carrier biogenesis.  Coat protein complexes also seem to play a regulatory role as scaffolds able to recruit many other proteins important for trafficking and transport.  We study the mechanisms underlying coat protein function using biochemical, structural, and cell biological approaches.

Our previous work revealed how a specific mutation in the human coat protein gene SEC23A contributes to an inherited craniofacial disease, by affecting assembly of the five-subunit COPII protein complex at the endoplasmic reticulum.  During these studies we took advantage of several powerful biochemical assays to study the function of this coat protein complex in vitro.  Future work in our lab on the human COPII coat will aim to address the role of coat protein complexes in cytoskeleton-directed movement of membrane transport carriers.  After formation, many transport carriers are actively conveyed along cytoskeletal elements by molecular motors.  At present, little is known about how transport carriers interact with these motors, and whether coat proteins might play an important role. 

The other project in our lab is investigation of the structure and function of the “exomer” coat.   Exomer is a novel fungal protein complex responsible for the transport of select proteins in the late secretory pathway.  Exomer is not related to any other known coat protein complexes, and therefore represents an exciting opportunity for study.  Exomer-based transport appears to be polarized, directing proteins to specific sub-domains of the plasma membrane.  Proteins transported by exomer are also somehow localized in a cell-cycle dependent manner.  We seek to understand how exomer deforms membranes into vesicles and acts as a receptor for vesicle cargo.  We also plan to investigate how exomer is involved in the regulation of polarized, cell-cycle dependent transport.  These interesting aspects of exomer function represent fundamental biological processes, found in human cells, operating in the genetically amenable S. cerevisiae.  We are using a wide range of structural, biochemical, and cell biological tools to investigate exomer function.

Recent Publications:

Fromme, J.C., Orci, L., Schekman, R. (2008) Coordination of COPII vesicle trafficking by Sec23. Trends in Cell Biology (in press).

Fromme, J.C., Ravazzola, M., Hamamoto, S., Al-Balwi, M.A., Eyaid, W., Boyadjiev, S.A., Cosson, P., Schekman, R., and Orci, L. (2007) The genetic basis for a craniofacial disease provides insight into COPII coat assembly. Developmental Cell 13: 623-634.

Kim, J., Thanabalasuriar, A., Chaworth-Musters, T., Fromme, J.C., Frey, E.A., Lario, P.I., Metalnikov, P.,  Rizg, K., Thomas, N.A.,  Lee, S.F., Hartland, E.L., Hardwidge, P.R., Pawson, T., Strynadka, N.C., Finlay, B.B., Schekman, R., Gruenheid, S. (2007) The bacterial virulence factor NleA inhibits cellular protein secretion by disrupting mammalian COPII function. Cell Host & Microbe 2: 160-171.

Boyadjiev, S.A., Fromme, J.C., Bin, J., Chong, S.S., Nauta, C., Hur, D.J., Zhang, G., Hamamoto, S., Schekman, R., Ravazzola, M., Orci, L., Eyaid, W. (2006) Cranio-lenticulo-sutural dysplasia is caused by a SEC23A mutation leading to abnormal ER-to-Golgi trafficking.  Nature Genetics 10: 1192-1197.

Fromme, J.C. and Schekman, R. (2005) COPII-coated vesicles: flexible enough for large cargo?  Curr. Opin. Cell Biol. 17: 345-352.

Search PubMed for Dr. Fromme’s publications.