Michael Summers

Ph.D. Emory University 1984; B.S. University of West Florida 1980

Our research efforts are aimed at understanding how retroviruses assemble and how they specifically recognized and package their genetic material.  Over the past decade or so, we and others have determined the 3D structures of several isolated protein components that make up HIV-1 (the retrovirus that causes AIDS).  We now wish to understand how these components interact with each other and with cellular constituents.  We are also interested in understanding how these intermolecular interactions change when the initially-formed retrovirus matures and become infectious.  In the long term, we would like to use the basic structural and functional information obtained to design new therapeutic approaches for the treatment of AIDS and other human diseases caused by retroviruses.

NMR-based structural studies indicate that the cellular phosphatidylinosititde, PIP2 (yellow) binds to a conserved cleft on the HIV-1 matrix protein, triggering myristate (green) exposure and membrane binding.

1. Ding, P., Kharytonchyk, S., Kuo, N., Cannistraci, E., Flores, H., Chaudhary, R., Sarkar, M., Dong, X., Telesnitsky, A., Summers, M. F. 5ʹ-Cap Sequestration is an Essential Determinant of HIV-1 Genome Packaging, Proc. Natl. Acad. Sci. USA 118, e2112475118 (2021).
2. Brown, J. D., Kharytonchyk, S., Chaudry, I., Iyer, A. S., Carter, H., Becker, G., Desai, Y., Glang, L., Choi, S. H., Singh, K., Lopresti, M. W.,  Orellana, M., Rodriguez, T., Oboh, U., Hijji, J., Ghinger, F. G., Stewart, K., Francis, D., Edwards, B., Chen, P., Case, D. A., Telesnitsky, A., Summers, M. F., “Structural Basis for Transcriptional Start Site Control of HIV-1 RNA Fate,” Science 386, 413-417 (2020).
3. Ding, P., Kharytonchyk, S., Waller, A., Mbaekwe, U., Basappa, S., Kuo, N., Frank, H. M., Quasney, C., Kidane, A., Swanson, C., Van, V., Sarkar, M., Cannistraci, E., Chaudhary, R., Flores, H., Telesnitsky, A., Summers, M. F., “Identification of the initial nucleocapsid recognition element in the HIV-1 RNA packaging signal,” Proc. Natl. Acad. Sci. U.S.A, 117, 17737-17746 (2020).
4. Saad, J. S., Loeliger, E., Luncsford, P., Liriano, M., Tai, J., Kim, A., Miller, J., Joshi, A., Freed, E. O., Summers, M. F. “Point mutations in the HIV-1 matrix protein turn off the myristyl switch”, J. Mol. Biol. 366, 574-585 (2007).
5. Zhou, J., Bean, Rebecca L., Vogt, V. M., Summers, M. F. “Solution Structure of the Rous Sarcoma Virus Nucleocapsid Protein:mY RNA Packaging Signal Complex”, J. Mol. Biol. 365, 453-467 (2006).
6. Saad, J. S., Miller, J., Tai, J., Kim, A., Ghanam, R. H., Summers, M. F. “Structural basis for targeting HIV-1 Gag proteins to the plasma membrane for virus assembly,” Proc. Natl. Acad. Sci. U.S.A., 103, 11364-11369 (2006).
7. Summers, M. F., Hrabowski, F. A. III, “Preparing minority scientists and engineers,” Science 311, 1870-1871 (2006).
8. D’Souza, V., Summers, M. F. “How retroviruses recognize and package their RNA genomes,” Nature Reviews Microbiology 3, 643-655 (2005).
9. D’Souza, V. D., Summers, M. F., ‘Structural Basis for Packaging the Dimeric Genome of Moloney Murine Leukemia Virus,’ Nature 431, 586-590 (2004).

Funding