NON-REDUNDANT ROLES OF COPPER TRANSPORTERS ATP7A AND ATP7B IN NORADRENERGIC SIGNALING

Abstract

Menkes disease and Wilson disease are debilitating neurometabolic disorders caused by mutations in the copper (Cu) transporters ATP7A and ATP7B, respectively. In either disease, normalization of systemic Cu levels often does not eliminate neurological deficits, suggesting dysregulated Cu homeostasis within vulnerable neuronal populations. However, the specific roles of ATP7A and ATP7B and the extent of their functional redundancy in neurons remain poorly defined. Here, we selectively deleted Atp7a or Atp7b in noradrenergic neurons, which express both transporters and require Cu for catecholamine biosynthesis. ATP7A deletion reduced Cu levels in the locus coeruleus, disrupted dopamine-{beta}-hydroxylase localization, impaired norepinephrine synthesis, and induced proteomic signatures of defective vesicular trafficking and proteostasis, culminating in neurodegeneration and impaired regulation of energy balance and adaptive thermogenesis. In contrast, ATP7B deletion preserved Cu levels but altered intracellular Cu utilization, resulting in catecholamine imbalance, -synuclein upregulation, aberrant dopamine-{beta}-hydroxylase distribution, and dysregulated thermogenesis. These findings establish ATP7A and ATP7B as non-redundant regulators of noradrenergic function within neural circuits governing metabolic and energy homeostasis and provide a mechanistic framework for persistent neurological pathology independent of systemic Cu levels.