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Reciprocal modulation of function between the D 1 and D 2 dopamine receptors and the Na + /K + ‐ATPase, a novel member of the dopamine receptor signalplex
Author(s) -
Hazelwood Lisa Ann,
Free R Benjamin,
Cabrera David M,
Neiman Jill,
Quinn Steven,
Sibley David R
Publication year - 2007
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/fasebj.21.5.a423
Subject(s) - chemistry , immunoprecipitation , receptor , dopamine , ouabain , stimulation , hek 293 cells , endogeny , biophysics , microbiology and biotechnology , medicine , endocrinology , biochemistry , biology , gene , sodium , organic chemistry
To determine the complement of proteins that make up the dopamine receptor (DAR) signalplex, we have employed a co‐immunoprecipitation assay for DARs coupled with mass spectrometry sequencing. Interacting proteins identified through these experiments include the Na + /K + ‐ATPase (NKA), a finding confirmed by Western analysis and reverse co‐immunoprecipitation experiments, which revealed specific D 1 and D 2 DAR interactions with NKA. To determine the impact of NKA on DAR function, biological assays were conducted in the presence of enhanced levels of NKA in HEK293 cells. In this system, over‐expression of NKA yields a dramatic decrease in total D 1 and D 2 DAR expression, with a concomitant functional decrease in DAR‐mediated regulation of cAMP production. Interestingly, pharmacological inhibition of either over‐expressed or endogenous NKA with ouabain enhanced DAR activity, as measured by cAMP production. Furthermore, over‐expression of DARs also impacts NKA function, causing a decrease in endogenous NKA activity as measured by 86 Rb uptake. Current studies are underway to determine the consequence of receptor stimulation or desensitization on DAR‐NKA interactions. Whether this interaction is direct or indirect will also be investigated. These preliminary data indicate that DARs and NKA can reciprocally regulate one another, providing a control mechanism for both DAR signaling and cellular ion balance. Support contributed by NIGMS PRAT program (LAH) and NINDS intramural program.