Graduate Program Information
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Associate Professor of Biochemistry and Biophysics
Ph.D. Johns Hopkins University 1980

Signal Transduction, Membrane Proteins, Yeast Molecular Biology

G protein signaling: G protein coupled receptors mediate cellular responses to a variety of sensory stimuli, hormones, growth factors, and neurotransmitters and are targets of a number of widely prescribed drugs. Signal transduction by G protein coupled receptors occurs when an activated receptor interacts with a trimeric G protein in the cytoplasm, causing the G protein to release a bound molecule of GDP and to replace it with a molecule of GTP. The mechanisms by which ligand binding leads to activation of the intracellular G protein remain poorly understood. We are using a combination of genetic and biochemical methods to study the yeast α-factor receptor that prepares yeast cells for mating in response to binding of the mating pheromone, α-factor. Components of this yeast signal transduction pathway are homologous to, and in some cases functionally interchangeable with, corresponding components of mammalian signaling systems. However, the ability to easily select or screen for functional and non-functional receptors in yeast allows rapid identification of receptors with interesting mutations from among a randomly mutagenized population in a way that is not possible in mammalian systems. We are currently analyzing classes of mutations that can provide information on the structure of the α-factor receptor, on interactions between receptors, and on the mechanism of activation of G proteins by receptors.

Genomic approaches to membrane protein structure and function: Although membrane proteins constitute 20-30% of the coding potential of genomes, methods for analyzing their structures and functions are still primitive compared to the approaches available for studies of soluble proteins. We are pursuing two projects that involve expression of membrane proteins on a genomic scale. One of these is the large scale expression and purification of membrane proteins encoded in the genomes of pathogenic protozoans for use in x-ray crystallography. The other, conducted in collaboration with the laboratories of Eric Phizicky and Elizabeth Grayhack, is the expression and purification of a complete set predicted reading frames from genome of bakers’ yeast Saccharomyces cerevisiae for use in identifying genes encoding membrane-related enzyme activities.

Recent Publications

Chloupkova M, Pickert A, Lee JY, Souza S, Trinh YT, Connelly SM, Dumont ME, Dean M, Urbatsch IL (2007) Expression of 25 Human ABC Transporters in the Yeast Pichia pastoris and Characterization of the Purified ABCC3 ATPase Activity. Biochemistry,

Bajaj A, Connelly SM, Gehret AU, Naider F, Dumont ME (2007) Role of extracellular charged amino acids in the yeast alpha-factor receptor. Biochim Biophys Acta, 1773:707-17

White MA, Clark KM, Grayhack EJ, Dumont ME (2007) Characteristics affecting expression and solubilization of yeast membrane proteins. J Mol Biol, 365:621-36

Gehret AU, Bajaj A, Naider F, Dumont ME (2006) Oligomerization of the yeast alpha-factor receptor: implications for dominant negative effects of mutant receptors. J Biol Chem, 281:20698-714

Wang Z, Stalcup LD, Harvey BJ, Weber J, Chloupkova M, Dumont ME, Dean M, Urbatsch IL (2006) Purification and ATP hydrolysis of the putative cholesterol transporters ABCG5 and ABCG8. Biochemistry, 45:9929-39

Gelperin DM, White MA, Wilkinson ML, Kon Y, Kung LA, Wise KJ, Lopez-Hoyo N, Jiang L, Piccirillo S, Yu H, Gerstein M, Dumont ME, Phizicky EM, Snyder M, Grayhack EJ (2005) Biochemical and genetic analysis of the yeast proteome with a movable ORF collection. Genes Dev, 19:2816-26

Alexandrov A, Vignali M, LaCount DJ, Quartley E, de Vries C, De Rosa D, Babulski J, Mitchell SF, Schoenfeld LW, Fields S, Hol WG, Dumont ME, Phizicky EM, Grayhack EJ (2004) A facile method for high-throughput co-expression of protein pairs. Mol Cell Proteomics, 3:934-8

Bajaj A, Celic A, Ding FX, Naider F, Becker JM, Dumont ME (2004) A fluorescent alpha-factor analogue exhibits multiple steps on binding to its G protein coupled receptor in yeast. Biochemistry, 43:13564-78

Roginskaya M, Connelly SM, Kim KS, Patel D, Dumont ME (2004) Effects of mutations in the N terminal region of the yeast G protein alpha-subunit Gpa1p on signaling by pheromone receptors. Mol Genet Genomics, 271:237-48

Celic A, Connelly SM, Martin NP, Dumont ME (2004) Intensive mutational analysis of G protein-coupled receptors in yeast. Methods Mol Biol, 237:105-20

Celic A, Martin NP, Son CD, Becker JM, Naider F, Dumont ME (2003) Sequences in the intracellular loops of the yeast pheromone receptor Ste2p required for G protein activation. Biochemistry, 42:3004-17

Martin NP, Celic A, Dumont ME (2002) Mutagenic mapping of helical structures in the transmembrane segments of the yeast alpha-factor receptor. J Mol Biol, 317:765-88

Erlenbach I, Kostenis E, Schmidt C, Serradeil-Le Gal C, Raufaste D, Dumont ME, Pausch MH, Wess J (2001) Single amino acid substitutions and deletions that alter the G protein coupling properties of the V2 vasopressin receptor identified in yeast by receptor random mutagenesis. J Biol Chem, 276:29382-92

Sommers CM, Martin NP, Akal-Strader A, Becker JM, Naider F, Dumont ME (2000) A limited spectrum of mutations causes constitutive activation of the yeast alpha-factor receptor. Biochemistry, 39:6898-909

Leavitt LM, Macaluso CR, Kim KS, Martin NP, Dumont ME (1999) Dominant negative mutations in the alpha-factor receptor, a G protein-coupled receptor encoded by the STE2 gene of the yeast Saccharomyces cerevisiae. Mol Gen Genet, 261:917-32

Martin NP, Leavitt LM, Sommers CM, Dumont ME (1999) Assembly of G protein-coupled receptors from fragments: identification of functional receptors with discontinuities in each of the loops connecting transmembrane segments. Biochemistry, 38:682-95

Sommers CM, Dumont ME (1999) Genetic Approaches for Studying the Structure and Function of G Protein-Coupled receptors in Yeast in Structure-Function Analysis of G Protein-Coupled Receptors. ( J. Wess, ed.) Vol. III of Receptor Biochemistry and Methodology, , John Wiley and Sons, New York, 141

Graduate students in my laboratory work toward a Ph.D. degree in the following program[s]:

Ph.D. in Biochemistry
Ph.D. in Biophysics
Ph.D. in Genetics

Ph.D. candidates in my laboratory may also be affiliated with these programs:

Contact Information

E-Mail: Mark_Dumont@urmc.rochester.edu

Mark Dumont
Department of Biochemistry and Biophysics
University of Rochester School of Medicine and Dentistry
601 Elmwood Ave, Box 712
Rochester, New York 14642

Office: Medical Center 3-6538
Telephone: (585) 275-2466; Fax: (585) 275-6007