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RGS7 complex formation and colocalization with the Gβ5 subunit in the adult rat brain and influence on Gβ5γ2‐mediated PLCβ signaling
Author(s) -
Liang JinJun,
Chen Hui Hong D.,
Jones Philip G.,
Khawaja Xavier Z.
Publication year - 2000
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(20000401)60:1<58::aid-jnr6>3.0.co;2-l
Subject(s) - colocalization , heterotrimeric g protein , g protein , gtpase activating protein , microbiology and biotechnology , protein subunit , biology , neuroscience , chemistry , signal transduction , biochemistry , gene
This study describes the colocalized distribution and dimeric complex formation between RGS7, a GTPase‐activating protein for several heterotrimeric Gα protein families, and the Gβ5 subunit in the adult rat brain. Confocal dual immunofluorescence labeling studies indicated a broad regional specificity in the cellular coexpression between RGS7 and Gβ5 within the cerebral cortical layers I and V–VI, hippocampal formation, caudate‐putamen, medial habenula, most thalamic nuclei, and cerebellar molecular and granular layers. In all instances, Gβ1–β4 immunoreactivities exhibited no observable colocalization with RGS7, despite their widespread codistribution throughout similar neuronal networks. Coimmunoprecipitation studies confirmed the selective protein–protein interaction between RGS7 and Gβ5 within brain regions that displayed immunohistochemical colocalization. The influence of RGS7 to modulate Gβ5γ2‐mediated phosphatidyl inositol (PI) production was examined in COS‐7‐cotransfected cells. In the presence of Gβ5γ2 only, intracellular PI accumulation was increased by 25% above basal levels; addition of RGS7 produced no significant alteration in Gβ5γ2‐mediated PI accumulation. A similar trend was exhibited when full‐length RGS7 was substituted with an RGS7 construct lacking the Gβ5‐interacting region (G protein gamma‐like domain; GGL domain) or with RGS4. In conclusion, RGS7/Gβ5 dimers occurred within most brain regions in which both proteins were cellularly coexpressed. However, an influence of RGS7 on Gβ5γ2‐mediated PLCβ signaling activity was not apparent, athough this was in COS‐7 cell transfection studies. J. Neurosci. Res. 60:58–64, 2000 © 2000 Wiley‐Liss, Inc.