Plays a key role in energy homeostasis by regulating the balance between energy storage and heat production. Functions by negatively regulating Ca(2+) signaling pathways that are involved in heat production and maintaining correct lipid storage in the fat body. Regulates Ca(2+) signaling pathways by reducing the activity of the calcium-transporting ATPase SERCA possibly by promoting uncoupling of SERCA ATP hydrolysis from calcium pumping. May also function in the nervous system to control feeding behavior. Interacts with SERCA. Detected in the larval fat body, salivary glands and wing imaginal disks (at protein level). No visible phenotype. However, flies are hypersensitive to the cold, hyperphagic and display elevated triglyceride stores resulting in an increased resistance to starvation. Heat production is impaired and flies are slow to recover after cold treatment. The size of the lipid droplets in larval fat bodies are significantly increased and flies display increased feeding. Total body glycogen is also significantly increased in adult females but not in males. Mutants also display an increase in calcium-dependent SERCA activity. No effect on levels of circulating sugars, glucose and trehalose. Belongs to the THADA family.