Myeloid Cell Leukemia 1 and Hexokinase 2 Directly Interact to Form a Glucose Metabolic Regulatory Axis.

Hexokinase 2 (HK2) catalyzes the first committed step of glucose metabolism-the conversion of glucose to glucose-6-phosphate-directing carbon flux into an array of metabolic pathways such as glycolysis, pentose phosphate pathways, amino acid biosynthesis, and others. Given its prominent role in glucose metabolism, it is critical we understand the regulation of HK2 to appreciate its role in normal physiological function as well as in disease states like cancers. In this study we sought to establish the ability of myeloid cell leukemia 1 (MCL1) to bind and regulate HK2 via its reverse Bcl-2 homology (rBH3) motifs. We employed a combination of biochemical and metabolic analysis in non-small cell lung cancer (NSCLC) cell models (H1299, A549, and NCI-H23) to establish a fundamental link between apoptosis and metabolic regulation. This demonstrates that MCL1 directly binds and enhances HK2 enzymatic activity through interactions with rBH3 on HK2. Consequently, we observe significant reductions in glucose-derived metabolites and impaired cellular metabolic plasticity with the disruption of the HK2-MCL1 interaction. These findings establish a novel mechanism by which anti-apoptotic proteins can directly regulate glucose metabolism.