FUNCTIONAL CHARACTERIZATION OF METABOLIC COMPLEXES FOR GLUCOSE METABOLISM IN LIVING HUMAN CELLS
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Author/Creator ORCID
Date
2020-01-01
Type of Work
Department
Chemistry & Biochemistry
Program
Chemistry
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Access limited to the UMBC community. Item may possibly be obtained via Interlibrary Loan thorugh a local library, pending author/copyright holder's permission.
This item may be protected under Title 17 of the U.S. Copyright Law. It is made available by UMBC for non-commercial research and education. For permission to publish or reproduce, please see http://aok.lib.umbc.edu/specoll/repro.php or contact Special Collections at speccoll(at)umbc.edu
This item may be protected under Title 17 of the U.S. Copyright Law. It is made available by UMBC for non-commercial research and education. For permission to publish or reproduce, please see http://aok.lib.umbc.edu/specoll/repro.php or contact Special Collections at speccoll(at)umbc.edu
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Abstract
Metabolic enzymes in glucose metabolism have long been studied for the formation of multienzyme complexes and their biological significance in living cells. We have recently demonstrated the existence of multienzyme complexes for glucose metabolism in living human cells, namely the glucosome. We has revealed that three different sizes of glucosomes regulate glucose-derived carbon flux between glycolysis and anabolic pathways in human cells: small-sized glucosomes are responsible for directing glucose flux into glycolysis whereas medium- and largesized glucosomes preferentially shunt glucose flux into the pentose phosphate pathway and serine biosynthesis, respectively. However, it has been challenging to characterize size-dependent functional roles of glucosomes in living cells. Here, we provide compelling evidence that glucosomes are dynamically regulated to meet metabolic demands in human cells. First, using flow cytometry and high-content imaging analysis, we have identified a functional interaction between the cell cycle and the reversible glucosome. We identified that small- and medium-sized glucosomes were dynamically oscillated during cell cycle progression, which regulate the degree of glucose flux into glycolysis and the pentose phosphate pathway. However, large-sized glucosomes were minimally oscillated during the cell cycle, indicating minimum oscilation of serine biosynthesis during the cell cycle. Second, we have revealed the relationship between glucosomes and epidermal growth factor (EGF) dependent signaling pathways. Along with Luminex multiplex assay and highcontent imaging analysis, we found that EGF-promoted ERK1/2 signaling pathways govern the formation of large-sized glucosomes, which indicates an increase of metabolic shunt from glycolysis to serine biosynthesis in the presence of EGF. Third, we have mapped a network of protein-protein interactions among the enzymes that participate in the assembly of glucosomes. Intracellular F�rster resonance energy transfer measurement revealed that phosphofructokinase 1 formed higher-ordered oligomeric structures and acted as a scaffold for the formation of glucosomes in living cells. Collectively, this work focuses on functional characterization of glucosomes and their biological roles in human cells, resulting in the advancement of our understanding of metabolic regulation by multienzyme complexes for novel therapeutic interventions in the treatment of human metabolic disorders.