Research Interests

My general research interests center on understanding membrane organization, particularly the organization of structural and functional domains within the plasma membrane. A primary research project explores the development and maintenance of plasma membrane domains during mammalian spermatogenesis using biochemical techniques, high resolution light microscopy, and, in collaboration with Dr. Dennis Koppel, biophysical analyses such as fluorescence photobleaching. A second project involves an ongoing collaboration with Dr. Peter Setlow in the department to analyze the dramatic changes in membrane organization that occur during sporulation in Bacillus subtilis.

As Deputy Director of the Center for Cell Analysis and Modeling, I oversee our light microscopy user facility, which provides access to state-of-the-art instrumentation in high-resolution fluorescence microscopy to the general research community. The Center for Biomedical Imaging Technology is also home to the NIH-funded National Resource for Cell Analysis and Modeling (NRCAM). NRCAM develops tools for quantitative cell biology research. Our approach is to combine high resolution quantitative imaging and biochemical analyses with mathematical modeling to develop computational simulations of specific cellular events. NRCAM has created the “Virtual Cell” modeling environment, a tool for creating spatially realistic mathematical models of cellular processes using a web-based interface that is freely available to the academic research community.

Selected Publications

Cowan, A. E. and P. G. Young. 1977. The formation of several mitochondrial enzymes during the cell cycle in heat-synchronized Tetrahymena pyriformis ST. Exp. Cell Res. 112: 79-87.

Cowan, A. E. and J. R. McIntosh. 1985. Mapping the distribution of differentiation potential for intestine, muscle, and hypodermis during early development in Caenorhabditis elegans. Cell 41: 923-932.

Cowan, A. E., P. Primakoff, and D. G. Myles. 1986. Sperm exocytosis increases the amount of PH-20 antigen of the surface of guinea pig sperm. J. Cell Biol. 103: 1289-1297.

Cowan, A. E., and D. G. Myles, and D. E. Koppel. 1987. Lateral diffusion of the PH-20 protein on guinea pig sperm: evidence that barriers to diffusion maintain plasma membrane domains in mammalian sperm. J. Cell Biol. 104: 917-923

Myles, D. G., D. E. Koppel, A. E. Cowan, B. M. Phelps, and P. Primakoff. 1987. Rearrangement of sperm surface antigens prior to fertilization. Ann. N. Y. Acad. Sci. 513: 262-273.

Primakoff, P., A. E. Cowan, H. Hyatt, J. Tredick-Kline, and D. G. Myles. 1987. Purification of the guinea pig sperm PH-20 antigen and detection of an endoproteolytic activity that cleaves the antigen into two disulfide-linked fragments. Biol. Reprod. 38:921-934.

Primakoff, P., W. Lathrop, L. Woolman, A. E. Cowan, and D. G. Myles. 1988. Fully effective contraception in male and female guinea pigs immunized with the sperm protein PH-20. Nature 335: 543-546.

Cowan, A. E., D. G. Myles, and D. E. Koppel. 1991. Migration of the guinea pig sperm membrane protein PH-20 from one localized domain to another does not occur by a simple diffusion-trapping mechanism. Dev. Biol. 114: 189-198.

Cowan, A. E. and D. G. Myles. 1993. Biogenesis of surface domains during spermiogenesis in the guinea pig. Dev. Biol. 155: 124-133.

Koppel, D. E., F. Morgan, A. E. Cowan, J. H. Carson. 1994. Scanning concentration correlation spectroscopy using the confocal laser microscope. Biophys. J. 66: 502-507.

Magill, N., A. E. Cowan, D. E. Koppel, and P. Setlow. 1994. The internal pH of the forespore compartment of Bacillus megaterium decreases by about 1 pH unit during sporulation. J. Bacteriol. 178:2204-2210.

Carrol, D. J., E. Dikegoros, D. E. Koppel, and A. E. Cowan. 1995. Surface expression of the pre- subunit of fertilin is regulated at a post-translational level in guinea pig spermatids. Dev. Biol. 168: 429-437.

MaGill, N. G., A. E. Cowan, M. A. Leyva-Vasquez, M. Brown, D. E. Koppel, and P. Setlow. 1996. Analysis of the relationship between the decrease in pH and accumulation of 3-phosphoglyceric acid in developing forespores of Bacillus species. J. Bacteriol. 178: 2204-2210.

Cowan, A. E., L. Nakhimovsky, D. G. Myles, and D. E. Koppel. 1997. Barriers to diffusion of plasma membrane proteins form early during guinea pig spermiogenesis. Biophys. J. 73: 507-516/

Nakayama, T. A., W. Zhang, A. E. Cowan, and M. Kung. 1998. Mutagenesis studies of human red opsin: Trp-281 is essential for proper folding and protein-retinal interactions. Biochemistry 37: 17487-17494.

Ragkousi, K., A. E. Cowan, M. A. Ross, and P. Setlow. 2000. Analysis of nucleoid morphology during germination and outgrowth of spores of Bacillus species. J. Bacteriol.182:5556-5562.

Carson, J. H., A. E. Cowan and L. M. Loew. 2001. Computational cell biologists snowed in at Cranwell. Trends in Cell Biol. 11:236-238.

Cowan, A. E., D.E. Koppel, L.A. Vargas, and G. R. Hunnicutt. 2001. Guinea pig fertilin exhibits restricted lateral mobility in epididymal sperm and becomes freely diffusing during capacitation. Dev. Biol. 236:502-536.

Setlow, B., C. A. Loshon, P. C. Genest, A. E. Cowan, C. Setlow, and P. Setlow. 2002. Mechanisms of killing spores of Bacillus subtilis by acid, alkali and ethanol. J. Applied Micro. 92: 362-375.

Smith, P.M., C. A. Heinrich, S. Pappas, J. J. Peluso, A. Cowan, and B. A. White. 2002. Reciprocal regulation by estradiol 17- of ezrin and cadherin-catenin complexes in pituitary GH3 cells. Endocrine 17: 219-228.

Melly E., A. E. Cowan, and P. Setlow. 2002. Studies on the mechanism of killing of Bacillus subtilis spores by hydrogen peroxide. J Appl. Microbiol. 93:316-25.

Arur, S., U. E. Uche, K. Rezaul, M. Fong, V. Scranton, A. E. Cowan, W. Mohler, and David K. Han. Annexin I Is an Endogenous Ligand that Mediates Apoptotic Cell Engulfment. 2003. Devel. Cell. 4:587-98

Cowan, A. E., D. E. Koppel, B. Setlow, and P. Setlow. 2003. A soluble protein is immobile in dormant spores of Bacillus subtilis, but exhibits rapid mobility in the germinated spores: implications for spore dormancy. Proc. Nat. Acad. Sci. USA. 100:4209-4214.

Setlow, B., A. E. Cowan, and P. Setlow. 2003. Germination of spores of Bacillus subtilis with dodecylamine. J. App. Micro. 95:637-648.

Smith, P. M., A. Cowan, S. L. Milgram, and B. A. White. 2003. Tissue-specific regulation by estrogen of ezrin and ezrin/radixin/moesin-binding protein 50. Endocrine 22: 119-126.

Smith, P. M., Cowan, A. and White, B. A. 2004. The LDL Receptor is regulated by estrogen and forms a functional complex with the estrogen-regulated protein ezrin in pituitary GH3 somatolactotropes. Endocrinology. In press.

Cowan, A. E., E. M. Olivastro, D. E. Koppel, C. A. Loshon, B. Setlow and P. Setlow. 2004 Lipids in the inner membrane of dormant spores of Bacillus species are largely immobile. Proc. Nat. Acad. Sci. USA. 101: 7733-7738.

Paik J.H., A. Skoura, S.S Chae, A.E Cowan, D.K Han, R.L Proia, T. Hla. 2004. Sphingosine 1-phosphate receptor regulation of N-cadherin mediates vascular stabilization. Genes Dev. 18: 2392-403.