Molecular Cell & Developmental Biology
225 Sinsheimer Laboratories
Phone: 831.459.4986
Fax: 831.459.3139
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BARRY BOWMAN Professor of MCD Biology B.A., University of Wisconsin, Milwaukee Ph.D., University of Michigan 1975-1979: Post-Doc at Yale University BOWMAN LAB

225 Sinsheimer Laboratories University of California Santa Cruz, CA 95064 phone 831.459.2245 fax 831.459.3139 bowman@biology.ucsc.edu office hours

Membrane Proteins: Biochemistry and Cell Biology
One third of the genes in all organisms encode membrane proteins, most of which transport molecules from one compartment to another. We use Neurospora crassa as our model organism.  The complete genome has been sequenced for this filamentous fungus. It has 10,000 genes, twice the number in yeast, and a complete collection of knockout mutants is being generated.

The vacuolar ATPase

In the past, the focus of our research has been on one of the major ion pumps in the cell, the vacuolar ATPase. Found in all components of the endomembrane system within cells, it is a large, complex enzyme that generates an electrochemical gradient for protons. This enzyme is composed of the products of at least 14 genes. It has an amazing mechanism, coupling the movement of protons to the function of a rotary motor that spins at 10,000 rpm. Some of the questions we have addressed are:

•    What are the functions of the subunits in the vacuolar ATPase? Do some of these subunits mediate the regulation of the enzyme and its interaction with other proteins in the cell?

•    What are the roles of the vacuolar ATPase in the cell? We found that disruption of genes that encode subunits of the vacuolar ATPase causes severe morphological changes. Analysis of these mutants may allow us to determine how the enzyme is involved in phenomena such as calcium homeostasis.

•    What is the mechanism of action of drugs that inhibit the vacuolar ATPase? We have discovered that several different kinds of antibiotics are potent inhibitors of the vacuolar ATPase. Other labs are trying to develop these drugs for use in treating diseases such as osteoporosis.  By generating mutant forms of the vacuolar ATPase we have determined the binding site of one class of these antibiotics.  The data have allowed us to make a high resolution model for the structure of the proton-binding polypeptides in the enzyme.

Calcium Transport Proteins

Where is calcium in the cell and how does it get there?  Calcium is an important signalling molecule.  Release and uptake of calcium by organelles generates changes in concentration in local areas of the cytosol.  Surprisingly little is known about the mechanism by which calcium is sequestered in different organelles or transported in and out of the cell. 

We have identified 11 genes that appear to encode calcium transport proteins.  Some of these are pumps, using the energy of ATP to move calcium.  Other proteins are carriers that may couple the transport of calcium with the movement of Na+ or H+.  By using knockout strains, or by tagging these proteins with GFP, we hope to identify the location and role of each one in the cell.

Selected Publications
Bowman, B.J., McCall, M.E., Baertsch, R., and Bowman, E.J. (2006) A Model for the Proteolipid Ring and Bafilomycin/Concanamycin Binding Site in the Vacuolar ATPase of Neurospora crassa. J. Biol. Chem. 281 (42):31885-31893

Chavez, C., Bowman, E.J., Reidling, J.C., Haw, K.H., and Bowman, B.J. (2006) Analysis of strains with mutations in six genes encoding subunits of the V-ATPase: Eucaryotes differ in the composition of the Vo sector of the enzyme. J. Biol. Chem. 281(37):27052-27062

Bowman, E.J. and Bowman, B.J. (2005) V-ATPases as Drug Targets. J. Bioenergetics and Biomembranes, 37:431-435

Wang X, Bowman EJ, Bowman BJ, and Porco JA Jr. Total synthesis of the salicylate enamide macrolide oximidine III: application of relay ring-closing metathesis. Angew Chem Int Ed Engl. 5;43(27):3601-5 (2004).

Zelter A, Bencina M, Bowman BJ, Yarden O, Read ND. A comparative genomic analysis of the calcium signaling machinery in Neurospora crassa, Magnaporthe grisea, and Saccharomyces cerevisiae. Fungal Genet Biol. 41(9):827-41 (2004).

Bowman EJ, Graham LA, Stevens TH, Bowman BJ. The bafilomycin/concanamycin binding site in subunit c of the V-ATPases from Neurospora crassa and Saccharomyces cerevisiae. J Biol Chem. 6;279(32):33131-8 (2004).

Bowman, E.J., Gustafson, K.R., Bowman, B.J. and Boyd, M.R. Identification of a New Chondropsin Class of Antitumor Compound that Selectively Inhibits V-ATPases. J. Biol. Chem. 278(45):44147-52 (2003).

Shen, R., Lin, C.T., Bowman, E.J., Bowman, B.J. and Porco, J.A. Lobatamide C: Total Synthesis, Stereochemical Assignment, Preparation of Simplified Analogues, and V-ATPase Inhibition Studies. J. Am. Chem. Soc. 125:7889-7901 (2003).

Bowman, B.J., and Bowman, E.J. Mutations in subunits c of the vacuolar ATPase confer resistance to bafilomycin and identify a conserved anitbiotic binding site. J. Biol. Chem. 227: 3965-3972 (2002).

Margolis-Clark, E, Hunt, I, Espinosa, S, and Bowman, B. J. Identification of the gene at the pmg locus, encoding System II, the general amino acid transporter in Neurospora crassa. Fungal Genetics and Biology 33:127-135 (2001).

Boyd, M. R., Farina, C., Belfiore, P., Gagliardi, S., Kim, J. W. Hayakawa, Y., Beutler, J. A., McKee, T. C. Bowman, B. J., and Bowman, E. J. Discovery of a novel antitumor benzolactone enamide class that selectively inhibits mammalian vacuolar-type (H+)-ATPases, J. Pharm. Exp. Therapeutics 297:114-120 (2001).

Tenney, K., Hunt, I., Sweigard, J., Pounder, J. I., McClain, C., Bowman, E. J., and Bowman, B. J. Hex-1, a gene unique to filamentous fungi, encodes the major protein of the Woronin body and functions as a plug for septal pores. Fungal Genetics and Biology 31:205-217 (2000).

Bowman, E.J., and Bowman, B.J. Cellular role of the V-ATPase in Neurospora crassa: analysis of mutants resistant to concanamycin or lacking the catalytic A subunit. J. Exp. Biol. 203: 97-106 (2000).

Bowman, E.J., Kendle, R. and Bowman, B.J. Disruption of vma-1, the gene encoding the catalytic subunit of the vacuole H+-ATPase, causes severe morphological changes in Neurospora crassa. J. Biol. Chem. 275:167-176 (2000).

Margolles-Clark, E., Tenney, K., Bowman, E.J., and

Bowman, B.J. The structure of the vacuolar ATPase in Neurospora crassa. J. Bioenerg. Biomembranes, 31:29-37 (1999).

Bowman, B.J. Neurosporapepsin, in Handbook of Proteolytic Enzymes, pp. 864-865, A.J. Barrett, N.D. Rawlings and J.F. Woessner, eds., Academic Press (1998).

Bowman, E.J., and Bowman, B.J. Purification of vacuolar membranes, mitochondria, and plasma membranes from Neurospora crassa and modes of discriminating among the different H+-ATPases, in Biomembranes, pp. 861-872, L.

Packer and S. Fleischer, eds,, Academic Press (1997).

Hunt, I.E. and Bowman, B.J. The intriguing evolution of the “b” and “G” subunits in F-type and V-type ATPases: Isolation of the vma-10 gene from Neurospora crassa. J. Bioenerg. Biomembr. 29:533-540 (1997).