PROJECT SUMMARY Human variants in the cytoskeleton-associated protein ankyrin-B (AnkB) have been identified as risk factors for metabolic disorders, including type 2 diabetes and obesity. Mice harboring these variants exhibit AnkB deficiency in metabolic tissues including white (WAT) and brown adipose tissue (BAT), and develop age and diet-dependent adiposity, insulin resistance, and glucose mishandling. Simultaneous AnkB deficiency in WAT and BAT also lead to lipid accumulation in BAT (BAT “whitening”) and to decreases in energy expenditure and oxygen consumption. These findings suggest that AnkB may function as an important regulator of lipid metabolism and systemic metabolic regulation through its unexplored roles in BAT. The overarching goal of this study is to elucidate the cell-autonomous roles of AnkB in BAT. We hypothesize that AnkB regulates lipogenesis in BAT and is required for maintaining the energetic and glucose-handling capacity of BAT in response to metabolic stressors. To answer these questions, we proposed to determine the molecular mechanism of association with AnkB modulation of glucose handling and lipid metabolism in brown adipocytes (aim 1). Additionally, we will define how AnkB deficiency in BAT regulates energy balance and systemic metabolic homeostasis in response to the metabolic stressors, such as aging and high-fat diet (aim 2). Completion of the proposed studies will provide functional insights into AnkB’s contribution to BAT physiology and metabolic homeostasis. The proposed work will also shed light into the pathophysiological mechanism through which human AnkB variants contribute to metabolic diseases.