大象传媒

Mechanisms of Cell Desensitization: Regulators of G protein Signaling

The Dohlman lab has for more than 30 years invested in training the next generation of research scientists. The lab fosters a culture of shared responsibility and cooperation, and welcomes individuals from diverse backgrounds and who bring new perspectives to the research endeavor. In 2019 Dr. Dohlman was awarded the Office of Graduate Education Excellence in Basic Science Mentoring聽Award.

The lab’s research is centered on ,听听补苍诲 (GPCRs). Interest in these began, as a graduate student with , with the cloning and sequencing of the first neurotransmitter GPCR (Dixon et al. Nature 1986). GPCRs are the target of two thirds of all hormones and neurotransmitters, as well as a third of all pharmaceuticals.

GPCRs are conserved in evolution and are even found in the simplest eukaryotes. The lab has long been conducting large-scale genomic and proteomic analysis in yeast to identify mutants with altered signaling and desensitization properties. Work in yeast led to the identification and characterization of the first RGS proteins (Dohlman et al. Mol Cell Biol 1995), which inactivate G proteins by accelerating their GTPase activity.

Thus, GPCRs and RGS proteins have opposing actions, activating and inactivating G proteins, respectively.

In addition to RGS proteins, the lab identified enzymes that regulate G proteins through聽phosphorylation and dephosphorylation聽(Clement et al.聽Sci Signal聽2013;聽Torres et al.聽J Biol Chem聽2011), as well as ubiquitination听补苍诲聽deubiquitination (Cappell et al.聽Mol Cell聽2010;聽Torres et al.聽J Biol聽Chem聽2009; Wang et al.聽J Biol Chem聽2005).聽The lab pioneered the use of mass spectrometry to map聽sites of ubiquitination (Marotti et al. Biochemistry 2002) and demonstrated聽endomembrane signaling by G proteins (Slessareva et al. Cell 2006).

In recent years the lab has been investigating G protein mutants linked to human disease, most notably uveal melanoma (Gq) and developmental and epileptic encephalopathy (Go). These variant proteins are characterized at the molecular and cellular level, and with goal of developing novel therapeutics.

SELECTED PUBLICATIONS

• Knight, K. M., Krumm, B. E., Kapolka, N. J., Ludlam, W. G., Cui, M., Mani, S., Prytkova, I., Obarow, E. G., Lefevre, T. J., Wei, W., Ma, N., Huang, X-P., Fay, J. F., Vaidehi, N., Smrcka, A. V., Slesinger, P. A., Logothetis, D. E., Martemyanov, K. A., Roth, B. L., and Dohlman, H. G., A neurodevelopmental disorder mutation locks G proteins in the transitory pre-activated state. Nature Communications, 15, 6643. doi.org/10.1038/s41467-024-50964-z2024, 2024.
• Knight, K. M., Obarow, E. G., Wei, W., Mani, S., Esteller, M. I., Cui, M., Ma, N., Martin, S. A., Brinson, E., Hewitt, N., Soden, G. M., Logothetis, D. E., Vaidehi, N., Dohlman, H. G., Molecular annotation of G protein variants in a neurological disorder. Cell Reports, 42:113462, 2023.
• Hewitt, N., Ma, N., Arang, N., Martin, S. A., Prakash, A., DiBerto, J. F., Knight, K. M., Ghosh, S., Olsen, R. H. J., Roth, B. L., Gutkind, J. S., Vaidehi, N., Campbell, S. L., and Dohlman, H. G., Catalytic-site mutations confer multiple states of G protein activation. Science Signaling, 16:771:eabq7842, 2023.
• Knight, K. M., Ghosh, S., Campbell, S. L., Lefevre, T., Olsen, R. H. J., Smrcka, A. V., Valentin, H. V., Yin, G., Vaidehi, N., and Dohlman, H. G., A universal allosteric mechanism for G protein activation. Molecular Cell, 81:1-13, 2021.
• English, J. G., Shellhammer, J. P., Malahe, M., McCarter, P. C., Elston, T. C. and Dohlman, H. G., MAPK feedback encodes a switch and timer for tunable stress adaptation in yeast. Science Signaling 8:359:ra5, 2015.
• Dixit, G., Kelley, J. B., Houser, J. R., Elston, T. C. and Dohlman, H. G., Cellular noise suppression by the regulator of G protein signaling Sst2. Molecular Cell 55:85-96, 2014.
• Isom, D. G., Sridharan, V., Baker, R., Clement, S. T., Smalley, D. M. and Dohlman, H. G., Protons as second messenger regulators of G protein signaling. Molecular Cell 51:531-538, 2013.
• Clement, S. T., Dixit, G. and Dohlman, H. G., Regulation of yeast G聽protein signaling by the kinases that activate the AMPK homolog Snf1. Science Signaling 6:ra78, 2013.
• Cappell, S. D., Baker, R., Skowyra, D. and Dohlman, H. G., Systematic analysis of essential genes reveals important regulators of G protein signaling. Molecular Cell 38:746-57, 2010.
• Hao, N., Nayak, S., Behar, M., Shanks, R. H., Nagiec, M. J., Errede, B., Hasty, J., Elston, T. C. and Dohlman, H. G., Regulation of cell signaling dynamics by the protein kinase-scaffold Ste5. Molecular Cell 30:649-56, 2008.
• Slessareva, J. E., Routt S. M., Temple, B., Bankaitis, V. A. and Dohlman, H. G., Activation of the phosphatidylinositol 3-kinase Vps34 by a G protein a subunit at the endosome. Cell 126:191-203, 2006.
• Ballon, D. R., Flanary, P. L., Gladue, D. P., Konopka, J. B., Dohlman, H. G. and Thorner, J., DEP-domain-mediated regulation of GPCR signaling responses. Cell 126:1079-93, 2006
• Guo, M., Aston, C., Burchett, S. A., Dyke, C., Fields, S., Rajarao, S. J. R., Uetz, P, Wang, Y., Young, K. and Dohlman, H. G., The yeast G protein a subunit Gpa1 transmits a signal through an RNA-binding effector protein Scp160. Molecular Cell 12:517-24, 2003
• Dixon, R. A. F., Kobilka, B. K., Strader, D. J., Benovic, J. L.,听Dohlman, H. G., Frielle, T., Bolanowski, M. A., Bennett, C. D., Rands, E., Diehl, R. E., Mumford, R. A., Slater, E. E., Sigal, I. S., Caron, M. G., Lefkowitz, R. J. and Strader, C. D., Cloning of the gene and cDNA for mammalian beta-adrenergic receptor and homology with rhodopsin. Nature 321:75-9, 1986.