Chris Fromme
Associate Professor

Chris Fromme

Phone

607-255-1016

Address

Department of Molecular Biology & Genetics
457 Weill Hall
Cornell University
Ithaca, NY 14853-2703

Email

Web Sites

Department Profile
Lab Website

Background

Chris Fromme is an Associate 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.

Research Description

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. The Golgi complex is the primary sorting organelle in eukaryotic cells, and virtually all traffic out of the Golgi is controlled by GTPases of the Arf family. Arf GTPases are activated to their GTP-bound form at the Golgi by Arf-GEF (Guanine nucleotide Exchange Factor) proteins of the BIG/GBF family. Activated (GTP-bound) Arf GTPases recruit effectors that form vesicles and sort cargos. Although the basic mechanism of Arf activation – nucleotide exchange by the GEF domain – is well characterized, there are two important unresolved questions regarding the Golgi-localized Arf-GEFs: How is their GEF activity regulated? How do they achieve their specific localization? We study these and other mechanistic questions regarding Arf GTPase regulation using biochemical, structural, and cell biological approaches.

We are also investigating the structure and function of the "exomer" vesicle coat. Exomer is an Arf1-dependent protein complex responsible for the transport of select proteins in the late secretory pathway of most single-celled eukaryotes. Exomer is not related to any other known coat protein complexes, and therefore represents an exciting opportunity for study. Exomer-based transport is polarized, directing proteins to specific sub-domains of the plasma membrane. Some proteins transported by exomer are also localized in a cell-cycle dependent manner. We seek to understand how exomer cargo sorting is regulated spatiotemporally. We are using structural, biochemical, and cell biological tools to investigate exomer function.

Publications

Barfield, R.M., Fromme, J.C., and Schekman, R. (2009) The exomer coat complex transports Fus1p to the plasma membrane via a novel plasma membrane sorting signal in yeast. Mol. Biol. Cell 20: 4985-4996.

Fromme, J.C., Orci, L., Schekman, R. (2008) Coordination of COPII vesicle trafficking by Sec23. Trends in Cell Biology 18: 330-336.

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.

Click here for Dr. Fromme's PubMed listing.