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J Biol Chem. 2018 Dec 28;293(52):20085-20098. doi: 10.1074/jbc.RA118.004889. Epub 2018 Oct 19.

ATP7A and ATP7B copper transporters have distinct functions in the regulation of neuronal dopamine-β-hydroxylase.

Author information

1
From the Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
2
the Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon 97239.
3
the Department of Biological Chemistry, Johns Hopkins University, Baltimore, Maryland 21205, and.
4
the Department of Neuroscience, Brain Science Institute, Johns Hopkins University, Baltimore, Maryland 21205.
5
From the Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, lutsenko@jhmi.edu.

Abstract

The copper (Cu) transporters ATPase copper-transporting alpha (ATP7A) and ATPase copper-transporting beta (ATP7B) are essential for the normal function of the mammalian central nervous system. Inactivation of ATP7A or ATP7B causes the severe neurological disorders, Menkes disease and Wilson disease, respectively. In both diseases, Cu imbalance is associated with abnormal levels of the catecholamine-type neurotransmitters dopamine and norepinephrine. Dopamine is converted to norepinephrine by dopamine-β-hydroxylase (DBH), which acquires its essential Cu cofactor from ATP7A. However, the role of ATP7B in catecholamine homeostasis is unclear. Here, using immunostaining of mouse brain sections and cultured cells, we show that DBH-containing neurons express both ATP7A and ATP7B. The two transporters are located in distinct cellular compartments and oppositely regulate the export of soluble DBH from cultured neuronal cells under resting conditions. Down-regulation of ATP7A, overexpression of ATP7B, and pharmacological Cu depletion increased DBH retention in cells. In contrast, ATP7B inactivation elevated extracellular DBH. Proteolytic processing and the specific activity of exported DBH were not affected by changes in ATP7B levels. These results establish distinct regulatory roles for ATP7A and ATP7B in neuronal cells and explain, in part, the lack of functional compensation between these two transporters in human disorders of Cu imbalance.

KEYWORDS:

ATP7A; ATP7B; Menkes disease; SH-SY5Y cells; Wilson's disease; cellular regulation; constitutive secretion; copper transport; dopamine-β-hydroxylase; intracellular trafficking; locus coeruleus; noradrenergic; vesicles

PMID:
30341172
PMCID:
PMC6311498
[Available on 2019-12-28]
DOI:
10.1074/jbc.RA118.004889

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