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ATP modulates Ca 2+ uptake by TRPV6 and is counteracted by isoform‐specific phosphorylation
Author(s) -
AlAnsary Dalia,
Bogeski Ivan,
Disteldorf Barbara M. J.,
Becherer Ute,
Niemeyer Barbara A.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.09-141481
Subject(s) - phosphorylation , microbiology and biotechnology , homeostasis , chemistry , ankyrin repeat , downregulation and upregulation , gene isoform , adenosine triphosphate , kinase , biochemistry , biology , gene
Ca 2+ homeostasis requires balanced uptake and extrusion, and dysregulation leads to disease. TRPV6 channels are homeostasis regulators, are upregulated in certain cancers, and show an unusual allelespecific evolution in humans. To understand how Ca 2+ uptake can be adapted to changes in metabolic status, we investigate regulation of Ca 2+ ‐influx by ATP and phosphorylation. We show that ATP binds to TRPV6, reduces whole‐cell current increments, and prevents channel rundown with an EC 50 of 380 μΜ. By using both biochemical binding studies and patch‐clamp analyses of wild‐type and mutant channels, we have mapped one relevant site for regulation by ATP to residues within the ankyrin repeat domain (ARD) and identify an additional C‐terminal binding region. Stimulation of PKC largely prevented the effects of ATP. This regulation requires PKC βII and defined phosphorylation sites within the ARD and the C‐terminus. Both regulatory sites act synergistically to constitute a novel mechanism by which ATP stabilizes channel activity and acts as a metabolic switch for Ca 2+ influx. Decreases in ATP concentration or activation of PKC βII disable regulation of the channels by ATP, rendering them more susceptible to inactivation and rundown and preventing Ca 2+ overload.—Al‐Ansary, D., Bogeski, I., Disteldorf B. M. J., Becherer, U., Niemeyer, B. A. ATP modulates Ca 2+ uptake by TRPV6 and is counteracted by isoformspecific phosphorylation. FASEB J . 24, 425–435 (2010). www.fasebj.org