Title:Hexokinase and Glycolysis: Between Brain Cells Life and Death
Volume: 17
Issue: 2
Author(s): Larissa Rodrigues Souza da Mata, Lais Damásio dos Santos and Marcelo de Cerqueira Cesar*
Affiliation:
- Laboratory of Neuroscience and Proteomics, School of Animal Science and Food Engineering, University of São Paulo,
Av. Duque de Caxias Norte 225, Pirassununga SP, 13635-900, Brazil
Keywords:
Hexokinase, glycolysis, serine/threonine kinase Akt, neurons, VDAC, Alzheimer´s disease.
Abstract: Hexokinase catalyses the first regulatory step of the glycolytic pathway. We can say without
any exaggeration that both hexokinase and glycolysis are involved in the control of brain cells' life
and death. To perform these pivotal roles, hexokinase occurs in four different isoforms in mammalian
cells. Type I isozyme is best suited for energy generation, introducing glucose in glycolysis. In contrast,
Type II and Type III isoforms product is directed to generation of NADPH through the pentose
phosphate pathway, utilized in biosynthetic processes. Nevertheless, hexokinase has another unique
property to accomplish its multiple functions: the capacity for mitochondrial binding. Linked to its
role in apoptosis control, the binding of hexokinase inhibits the action of apoptosis inducers, such as
Bax, from initiating the release of intramitochondrial proteins. Akt mediates HKII binding to mitochondria.
Overexpression of the phosphatase SHIP2 reduces Akt activity and enhances apoptosis, emphasizing
the role of hexokinase in cell death. Furthermore, hexokinase also participates in cellular
signaling and functional regulation. Adding complexity to this multidimensional enzyme´s attributes,
glycolysis occurs in aerobic or anaerobic situations. “Aerobic glycolysis” participates in the control of
cell excitability, in synapse formation and neurite growth. Here we provide an overview of the multiple
roles of hexokinase and glycolysis in neuronal metabolic association with astrocytes, oligodendrocytes,
and microglia. We also provide an update on the role of hexokinase and glycolysis in microglia
activation and in brain aging and neurodegenerative diseases.