The overall goal of the lab is to study the role of energy homeostasis pathways in human disease using structural and chemical tools. Our lab focuses on two major fundamental pathways: O-GlcNAcylation and autophagy. The first major focus on the lab is on glycosylation, which plays a fundamental role in living organisms and is misregulated in several human diseases. A unique form of glycosylation in mammals involves the essential enzyme O-GlcNAc transferase (OGT), which dynamically transfers a single sugar on to nuclear and cytoplasmic proteins to modulate signaling, transcription, and protein degradation. This single enzyme is responsible for glycosylating over a thousand substrates. Aberrant OGT activity is associated with human diseases such as cancer, diabetes, obesity, and neurodegeneration. However, the biology of this modification is quite complex because of the abundance of substrates for a single enzyme. This complexity has prevented an understanding of which substrates are important for human diseases, how OGT recognizes them, and how metabolic changes alter the physiology of cells through this enzyme. We seek to better understand the mechanism of this fundamental enzyme through a combination of biochemistry, structural biology, and chemical biology. Our major goal is to clarify the complex role that nuclear and cytoplasmic protein glycosylation has in human disease. Autophagy is a conserved pathway that eukaryotic cells use to recycle materials from proteins to whole organelles for energy and quality control. It has recently been shown that cancer cells rely on autophagy to satisfy their increased energy demands and to resist chemotherapy. To study autophagy, our major goals are developing new chemical inhibitors of a key enzyme that initiates autophagy called ULK1. Our other goal is to find novel synthetic lethal interactors with autophagy by discovering other drugs that synergistically target cells when autophagy is inhibited. Our vision is to develop advance screening systems to better mimic tumors and look for new combinations of treatment that rely on blocking autophagy.

Public Health Relevance

Aberrant energy homeostasis and glycosylation is associated with several human diseases including cancer, diabetes, and obesity. A single enzyme (OGT) is responsible for all the protein glycosylation that occurs in the cytoplasm and nucleus; however, how this enzyme recognizes its substrates and which substrates are most important for human diseases are largely unknown. This proposal will examine the link between glycosylation and disease and will explore the role of a key energy homeostasis pathway, called autophagy, in cancer.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Unknown (R35)
Project #
5R35GM124838-03
Application #
9752600
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Maas, Stefan
Project Start
2017-09-18
Project End
2022-07-31
Budget Start
2019-08-01
Budget End
2020-07-31
Support Year
3
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Icahn School of Medicine at Mount Sinai
Department
Pharmacology
Type
Schools of Medicine
DUNS #
078861598
City
New York
State
NY
Country
United States
Zip Code
10029
Martin, Sara E S; Tan, Zhi-Wei; Itkonen, Harri M et al. (2018) Structure-Based Evolution of Low Nanomolar O-GlcNAc Transferase Inhibitors. J Am Chem Soc 140:13542-13545
May, Janine M; Owens, Tristan W; Mandler, Michael D et al. (2017) The Antibiotic Novobiocin Binds and Activates the ATPase That Powers Lipopolysaccharide Transport. J Am Chem Soc 139:17221-17224